Here are the answers and explanations for the practice exam in Chapter 15. Read over each question from Chapter 15 as you check your answers. Doing so reminds you what the question is about and serves as a helpful review. If you look at each question and the possible answers, you can also identify some of the traps that you may run across on the ASVAB.

You don’t have to be an algebra ace to determine whether you’re making progress through your review efforts. Simply compare the number of wrong answers you got on Practice Exam 1 (Chapter 13) against the number of wrong answers you got on this test. If you put the work in, you’ll probably find that you made fewer errors on Practice Exam 2.

By the time you’ve scored Practice Exam 2, you should have a good idea of your strengths and weaknesses. If some subjects or subtests still give you problems, keep studying — just follow the cross-references for some tips and additional practice questions. If you find you need in-depth study, check out Chapter 14, where I name some books on various subjects covered in the subtests.

The ASVAB is technically scored by comparing your raw score to the scores of other people, which produces a scaled score. Turn to Chapter 2 to find out how the ASVAB is scored.

Subtest 1: General Science Answers

The answers to the questions on the General Science subtest are fairly straightforward — you either know the answer or you don’t. This can be a hard subject to study for because General Science includes the entire scope of scientific disciplines. The good news is you may not even have to score well on this subtest — it depends on the job you’re interested in. See Appendix A for military jobs that require a good General Science score. You can find additional science practice questions in Chapter 8.

1. B

2. D

3. C

4. A

5. D

6. B

7. B

8. A

9. D

10. B

11. A

12. C

13. B

14. D

15. C

16. B

17. A

18. C

19. C

20. A

21. D

22. B

23. C

24. C

25. C

Subtest 2: Arithmetic Reasoning Answers

This subtest is one of the most important because it makes up a portion of your AFQT score, the score that determines your overall mental qualifications to enlist in the military.

If you think you need more in-depth study, review Chapters 6 and 7 or see whether you can find some high school–level math textbooks at your local library.

1. D. For each die, the probability of rolling a 5 is 1 out of 6 so the probability of not rolling a 5 is , or . With two dice, the probability of not rolling a 5 is , or .

2. C. Multiply $1,500 by 7%, or 0.07, and get $105. Then add $105 to $1,500 to find the answer, $1,605.

   Sometimes you can actually save time by not working the problem. In this problem, simply recognizing that the answer has to be more than $1,500 makes it obvious that Choices (A) and (B) are wrong. It also should be obvious that 7% of $1,500 has to be more than $7, so Choice (D) is also wrong. That only leaves the correct answer, Choice (C).

3. A. .
4. C. . Expanding the equation results in . You know that and . When you substitute these known values into the equation, you get . Solving for y results in .
5. C. There are 2 pints in a quart, and 4 quarts make up a gallon; therefore, a gallon contains pints, or 16 half-pints. One half-pint equals of a gallon.
6. D. First subtract the old cost from the new cost: . Then divide the difference by the old cost to find the percent difference: .
7. C. The aircraft travels 120 miles in 12 minutes, which is of an hour. Therefore, in (or 1 hour), it would travel or 600 miles. The aircraft is traveling 600 miles per hour.
8. D. Multiply 50 bushels by 8% to find the yield increase in bushels: . Add 4 bushels (the amount of the increase) to 50 bushels (the original yield) to determine that an 8% increase equals 54 bushels.
9. B. Convert the change to dollars or fractions of dollars and add:
   

   Subtract the total from $30.00 to determine how much money Junior has to borrow: .

10. B. Her commission for the week was $40 (because ). The ratio of her commission to her salary is 40:80, which can be reduced to 1:2.
11. C. A gallon consists of 4 quarts, and .
12. D. Four members is twice as many as two members. Multiply the number of days it would take four people to paint by 2 (that is, ) to determine how long it would take two people to do the same task.
13. A. Brian’s hourly wage is . Christina’s hourly wage is . .
14. C. The amount of time from 8:30 a.m. to 11:15 a.m. is 2 hours, 45 minutes. From 8:30 a.m. until 10:30 a.m. is 2 hours. From 10:30 until 11:15 is 45 minutes, or of an hour, for a total of hours.
15. C. At a rate of 7 documents per minute, the employee can shred 630 documents in 90 minutes. How do you come up with that number? Multiply 7 by 90 (the number of minutes in hours). Subtract 630 from 900 total documents to determine that after hours of shredding, 270 documents remain.
16. A. If the stereo depreciates 20%, the value of the stereo then becomes 80% of its original value. After depreciation, the value of the stereo the first year is $960 . The value of the stereo after the second year is $768 . $768 is Choice (A).
17. A. Divide the distance (135 miles) by the speed (45 miles per hour) to determine that Janet will take 3 hours to reach the city.
18. D. Multiply the price of the blouse by the amount of the discount: .
19. C. Subtract the original salary from the new salary to get the difference in salary: . Then divide the difference in salary ($40) by the original salary ($320) to determine the percent increase: .
20. B. A circle is 360 degrees, so 40 degrees is of a circle . To get the answer, multiply the circumference of the track by
21. B. Subtract $35.98 from $40.00 to get $4.02.
22. B. Subtract the time of the plane from the time of the balloon to determine how much longer it took the balloonist:
    
23. A. Divide the total cost by the number of boxes purchased to determine the cost per box: .
24. D. Multiply to determine how many more miles per gallon the car will get. The answer is 1. Then add the number of additional miles per gallon the car will get to the original number of miles per gallon the car gets to reach the new average: .
25. A. The minimum length of spike is equal to the diameter of the tree. To find the diameter of the tree, use the formula, , where and : ; ; .
26. D. Divide by . You can perform this operation by multiplying by the reciprocal of : . Divide 84 by 6, and the answer is 14.

27. C. First figure out how many stones will be needed along the 12-foot side of the patio and then how many stones will be needed along the 14-foot side of the patio. Then multiply those two numbers together to get the total number of stones required. Here’s the math: Convert 12 feet to inches: . The paving stones are 8 inches square, so divide 144 inches by 8 inches , which gives you 18 stones.

    Do the same math for the 14-foot length: , and . Therefore, 21 stones are needed on the 14-foot side.

    Now multiply the stones: , which is Choice (C).

28. D. Calculate the amount of the deduction by multiplying her salary by the percent deducted: . Subtract that product from the salary to determine the net pay: .
29. B. When the sum of two angles is 180 degrees, the angles are said to be supplementary to each other. To find the supplement, subtract 55 from 180: .
30. C. Multiply the height of the stack in feet by 12 to determine the height of the stack in inches: inches. Divide that number by 4 inches, the thickness of each board, to determine the number of pieces of lumber in the stack: .

Subtest 3: Word Knowledge Answers

Keep in mind that your score on the Word Knowledge subtest counts toward your AFQT score (see Chapter 1), so make sure you’re getting comfortable with this portion of the test.

If your score on the Word Knowledge subtest has improved since you took the first test, congratulations! If not, don’t be too surprised. Improving your score on this subtest in a short period of time is difficult, but it can be done. Review the information from Chapter 4 and set aside time each day (maybe several times a day, depending on how soon you plan on taking the ASVAB) to memorize words, roots, prefixes, and suffixes. Make sure you sink your dictionary into the additional practice questions at the end of Chapter 4, too.

1. C

2. A

3. A

4. C

5. B

6. B

7. D

8. B

9. B

10. C

11. C

12. B

13. D

14. B

15. A

16. D

17. A

18. C

19. B

20. A

21. C

22. C

23. D

24. A

25. D

26. B

27. B

28. D

29. A

30. A

31. C

32. C

33. D

34. B

35. D

Subtest 4: Paragraph Comprehension Answers

Like Word Knowledge, the Paragraph Comprehension subtest also counts toward your AFQT score. If you’re missing more answers than you should, review the info in Chapter 5 and concentrate on improving your analytical reading skills. For example, when you’re reading a news story online, ask yourself what the main point of an article is. Or when you finish a news story, set the paper down and try to remember what the president said about the budget deficit. Think of this technique as a workout for your mind.

1. B. The author is describing a quaint country setting.
2. B. The passage states that the brooks in the village run south, so the answer is Choice (B). A few miles north, the brooks run in an opposite direction (north).
3. B. The passage states that Panama revolted against Colombia, not that they fought over the canal, so Choice (A) is incorrect. The passage states that the foreign companies were unsuccessful in building the canal, so Choice (C) is incorrect. The United States, not Panama, built the canal, so Choice (D) is wrong. In the next to last sentence, the passage states that the U.S. was given rights to the land the canal occupied, making Choice (B) the correct answer.
4. D. According to the passage, a torn U.S. flag can be professionally mended, but a severely torn flag should be destroyed. The preferred method of destruction is by burning.
5. D. The passage states that guilds had economic and social purposes, so Choice (A) is incorrect. The passage states that guilds were similar to labor unions, so Choice (B) is incorrect. The passage states that guilds protected merchants and craftspeople; it says nothing about exploiting workers, so Choice (C) is incorrect. The third sentence states that some guilds held considerable economic power, but even small guilds protected members, making Choice (D) the correct answer.
6. D. According to the passage, it took more than four years for the government to believe that anyone had flown a heavier-than-air craft. The historic flight was in December 1903, and the Wright brothers delivered the first aircraft to the government in August 1908, 4.5 years later. The passage supports all the other statements.
7. C. Freud comments on the characteristics of memory throughout the entire passage.
8. A. The passage describes how troy and common weights are different, so Choice (B) is incorrect. Common and avoirdupois are the same system, so Choice (C) is incorrect. A troy ounce is 480 grains, so Choice (D) is incorrect. Choice (A) is the correct answer because the second sentence states that a common ounce is 437.5 grains, which is just shy of 438 grains.
9. B. The passage doesn’t address leading by example or use of technology by workers, so Choices (A) and (C) are incorrect. Maximizing worker performance is a result of leadership involvement, not a principle of leadership, making Choice (D) incorrect. The correct answer, showing interest in workers’ problems, is in the third sentence of the passage.
10. C. The passage doesn’t support Choices (A) or (B). The passage states that white blood cells are found in blood and bone marrow, so Choice (D) is wrong. The correct answer, Choice (C), can be found in the first sentence. The passage states that leukemia interferes with “the body’s ability to produce red blood cells.”
11. C. High intensity conflict is listed as a type of military operation (in the last sentence), not one of the four operational concepts.
12. C. The JV 2020 guides all the military services with its vision of future war fighting. Although Choice (D) is close, the passage doesn’t specifically reference military training.
13. B. Cytogenetics is the study of the cellular basis of inheritance; the text doesn’t support Choices (A), (C), or (D).
14. A. Nothing in the passage supports Choices (B) or (D). Although human genetics is an important subfield of genetics, nothing in the passage suggests that it’s the only concern of geneticists. Microbial genetics, as the passage mentions, is a subfield in genetics that has nothing to do with humans, so Choice (C) is incorrect. Choice (A) is the correct answer — the second sentence mentions genes and their transmission to offspring.
15. C. Nothing in the passage supports Choices (A), (B), or (D). Choice (C) is the correct answer because the last sentence in the passage states, “[Genetic counselors] advise couples and families on the chances of their offspring having specific genetic defects.” Note it does not state that genetic counselors use genetics to prevent offspring from inheriting defects, which is what Choice (D) states, making Choice (D) an incorrect answer.

Subtest 5: Mathematics Knowledge Answers

Although the military doesn’t expect you to be the next Einstein, a solid grasp of mathematics is important because math skills make up half of your AFQT score. If you’re still struggling on this subtest, it’s time to hit the books. (Actually, as much as you may feel like it, I don’t recommend that you literally hit the books — just study them.) See Chapter 6 for some more fun practice questions.

1. A. If two exponents have the same base, you can multiply them by keeping the base and adding the exponents together: .
2. A. To find area, multiply length times width . You have the width, so you need to find the length. For a rectangle, so plug in the values you know and solve for l. To determine the length, subtract two times the width from the perimeter: . Divide the answer by 2 to determine the length of one side: . Then multiply length times width to determine the area: .
3. D. The cube of 4 is , so 4 is the cube root of 64.
4. A. To convert this number to scientific notation, move the decimal point to the left until it’s to the immediate right of the first number, while counting the number of moves. In this case, you move it five places. The result is then multiplied by 10 raised to the power of the number of places the decimal point was moved. The exponent is positive here because the original number, 314,000, is larger than 3.14. Choice (B), , is equal to 0.0000314, so it’s incorrect.
5. C. A reciprocal is the number by which a number can be multiplied to produce 1. The reciprocal is 6, because .
6. A. You start with . Multiply both sides of the equation by x: or . Check by substituting 0.05 for x in the original equation.
7. C.
8. C. You start with . Solve the left side of the equation first. . Therefore, , which equals . Now isolate x by dividing both sides of the equation by 24: or . Check your answer by substituting 10 for x in the original equation.
9. B. Isolate x on one side of the equation. Subtract x from both sides of the equation and then add 6 to both sides:
   

   Check by substituting 11 for x in the original equation.

10. D. Solve for I. , or .
11. B. Multiply out what’s in parentheses. Then simplify and solve for x:
    
12. A. The area of a circle is . The number π is approximately 3.14, so means A is approximately 78.5 square inches.
13. D. Distribute the , simplify, and solve for x. Note that when you divide by a negative number, you have to switch the direction of the inequality sign.
    
14. B. For cylinders, . In this problem, . Assume is approximately 3.14. V is approximately equal to , or 141 cubic inches.
15. A. A right triangle has one right angle (one angle).
16. D. Parallelograms have opposite sides of equal length.
17. D. Angles measuring more than 90 degrees are obtuse angles.
18. B. This is a quadratic equation, which you solve by factoring. First factor out the –1; then factor the quadratic expression and solve for x:
    
19. B. Volume equals length times width times height . In this case, , so one edge of the box is 4 inches long (because 4 is the cube root of 64: ). Find the perimeter by adding the four sides together: .
20. C. You calculate volume by multiplying length times width times height . Because the edges are equal on a cube, each edge is 4 inches (because ). The area of one face of the cube is square inches, and because a cube has 6 sides, you multiply to find the surface area of the cube, 96 square inches.
21. C. is the same as . Multiply exponents with the same base by keeping the base and adding the exponents: .
22. D.
23. B. You start with . To solve, subtract from both sides of the equation and then take the cube root:
    
24. B. The formula to find the sum of a finite arithmetic sequence is , where n is the number of terms, a is the first term in the sequence, and b is the last term in the sequence. In this case there are 300 terms (n), and the first term is 1 and the final term is 300.
    
25. B. is the same as . Multiply exponents with the same base by keeping the base and adding the exponents: The second in the equation cannot be added into the first term because now they are not like terms, so the answer is Choice (B), . Tricky, eh?

Subtest 6: Electronics Information Answers

If you’re having difficulty defining the difference between AC and DC, you may want to spend some additional time studying basic electronic information. Reviewing Chapter 11 can help. You can also wrap your wires around the practice questions in that chapter as well.

On the other hand, you may not be interested in a military job that requires a decent score on this subtest (see Appendix A), in which case, try not to worry too much. Your main goal is to score well in all areas of the ASVAB. The better you do on each subtest, the more desirable you become as a candidate for all the available jobs.

1. A. A multimeter includes several pieces of test equipment, including an ammeter, which measures inline current.
2. A. Rotor bars are only on AC induction motors, not DC motors.
3. A. NTSC stands for National Television System Committee and, although gradually being replaced by ATSC (Advanced Television Systems Committee), NTSC is currently the broadcast standard in the U.S. Choice (B) is incorrect because RGB stands for red, green, and blue — the colors of light used to create an image. Although most televisions use this standard, it is not a broadcast standard. Choice (C) is incorrect because SECAM (Séquentiel couleur avec mémoire, or sequential color with memory) is a standard used in other countries. Choice (D) is RTSC, which stands for Raytheon Technical Services Company and is obviously not the correct answer.
4. A. In a closed circuit, one terminal is always positive, and the other is always negative.
5. C. Amperes (or amps) are the unit of measure of electric current. Hertz is the unit of measurement of frequency, not current. Current equals voltage divided by resistance. Resistance is measured in ohms. Therefore, neither voltage nor ohms can be the unit of measure for current.
6. B. The symbol is a fuse. Fuses are designed to blow (melt) if the current flowing through them exceeds a specified value.
7. C. This is code prescribed by the NEC (National Electric Code). Outlets within 6 feet of a sink need to be GFCI protected for safety reasons.
8. A. The symbol is a lamp. A lamp is a transducer that converts electrical energy to light.
9. C. Conventional circuit breaker handles have four positions: on, off, trip, and reset. When tripped, the handle moves to the middle position.
10. D. The smaller the wire, the larger the number.
11. D. Plastic does not conduct, and wood is a poor conductor. Aluminum is a good conductor but not better than copper.
12. A. A series circuit has only one path, so if you break the circuit’s path at any point, electricity stops flowing. An example of a series circuit is a string of Christmas lights that no longer works if a single bulb burns out.
13. B. In this case,
14. D. Potential equals voltage; low potential is anything less than 600 watts.
15. D. Glass is an insulator. Other insulators include plastics, paper, and rubber.
16. A. Ground wires are always green.
17. C. Amplitude modulation (AM) was the first type of audio modulation to be used in radio. It works well with high frequency (HF) and Morse code.
18. A. Silver is a better conductor, but it’s more brittle than copper and more expensive.
19. D. Oscillators produce high frequencies. An amplifier changes the amplitude of a signal. A regulator is a circuit that maintains a constant voltage. A transformer is a device that changes (transforms) the voltage at its input side to a different voltage on its output side.
20. B. When DC is applied to an AC appliance, the amount of resistance is less, so more current flows through the wire and heat builds up.

Subtest 7: Auto & Shop Information Answers

You need to do well on this subtest to qualify for certain military jobs (see Appendix A). If you care about those jobs and you’re missing more than a few questions on this subtest, it’s time for more extreme measures — like taking your mother’s car apart and putting it back together (or going back over Chapter 9).

1. D

2. D

3. B

4. A

5. C

6. C

7. C

8. C

9. D

10. A

11. A

12. C

13. B

14. C

15. A

16. C

17. D

18. D

19. B

20. B

21. A

22. D

23. B

24. D

25. B

Subtest 8: Mechanical Comprehension Answers

If you need to do well on the Mechanical Comprehension subtest (as in you’re hoping for a military career that requires a score for this subtest) but you’re still missing more answers than you should be, ask yourself whether your math skills need work. Go back to Chapters 6 and 7 if they do. Many of the formulas you need to know for this subtest require an understanding of arithmetic and basic algebra.

Usually, improving your arithmetic and basic algebra skills will improve your score on the Mechanical Comprehension subtest. Improving your knowledge of physics is also beneficial. Take a gander at Chapter 10.

1. C. A simple pulley gives no mechanical advantage, although it does make work easier by spreading out the work needed over several tries. The mechanical advantage is 1.
2. D. Moving Basket A to the right counterbalances the loss of cherries from Basket B.
3. A. Wheel B has to make more revolutions to cover the same ground as Wheel A, so it covers the distance more slowly.
4. C. You can calculate psi as . So in this problem, .
5. B. If you move Anvil A toward the center, Anvil B will move toward the ground.
6. B. The formula to determine mechanical advantage of an inclined plane is = . Plugging in the numbers gives you
   
7. C. Micrometers measure very small but not microscopic objects.
8. C. Reducing the weight on Side B will cause Side A to move toward the ground.
9. D. Objects rubbing together produce friction.
10. A. Normal atmospheric pressure (the average atmospheric pressure at sea level) is 14.7 psi.
11. D. Gears of unequal size can mesh properly as long as their teeth are of equal size.
12. C. Torsion springs coil or uncoil and produce a twisting action, not a direct pull; in other words, torsion springs apply torque.
13. B. To move a heavy object a few feet in height, the inclined plane is the most efficient device (of those listed) to use. Note: The mechanical advantage of an inclined plane is equal to the slope of the plane divided by the height. The longer the slope is (compared to the height), the greater the mechanical advantage will be.
14. B. Water expands when it freezes, possibly damaging engine components.
15. A. The load is closer to Anvil A, so it’s carrying the greater portion of the weight.
16. C. All the listed parts remain stationary except the lower block.
17. A. Apply the leverage formula: = :
    
18. C. The valve will open each time a high point of the cam hits it. The cam has three high points, so the valve will open three times per revolution.
19. A. Closing only Valves 3 and 4 keeps the water from leaving the tank.
20. C. Gears in mesh always turn in opposite directions.
21. B. If Gear 1 turns at 10 rpm, then Gear 2, which is half the size, turns twice as fast, at a rate of 20 rpm.
22. A. Opening Valves 1, 2, 4, and 8 allows the fuel to travel through the filters. Opening Valves 1, 2, and 3 doesn’t allow the fuel to travel through Filter D. Opening Valves 6, 7, and 8 doesn’t allow the fuel to travel through the filters. Opening Valves 4, 6, and 7 doesn’t allow fuel to travel to Reservoir B.
23. B. A yellow flame indicates too much fuel or not enough air. More air should be allowed to enter and mix with the gas. Thus, the fuel-air mixture is too rich.
24. A. The float measures the water level in the tank. If the tank overflows, the float is probably defective.
25. C. The 20-pound anvil and the 4-pound board weigh 24 pounds total or, divided by 2, 12 pounds per scale.

Subtest 9: Assembling Objects Answers

So far, only the Navy has elected to use scores from the Assembling Objects subtest and only for a few jobs. If you’re planning on joining the Navy and you’re interested in a Navy career that requires a score on this subtest (see Appendix A), review Chapter 12 for help on improving your score.

1. B

2. A

3. C

4. D

5. C

6. A

7. B

8. C

9. D

10. D

11. C

12. B

13. A

14. B

15. D

16. D

17. C

18. B

19. C

20. C

21. A

22. D

23. C

24. B

25. D