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12.Practice.Tests.for.the.SAT_2015-2016_1128p

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12 Practice <strong>Tests</strong> <strong>for</strong> <strong>the</strong> <strong>SAT</strong><br />

Practice Test Eleven Answers and Explanations I<br />

1005<br />

The ma<strong>the</strong>matical way of expressing "doubling to occur 24<br />

times" is 224.<br />

Getting to <strong>the</strong> Answer:<br />

The answer is <strong>the</strong> total growth that occurs, times <strong>the</strong><br />

original population. Again, total growth is 224. The original<br />

population is p.<br />

9. E<br />

Difficulty: Medium<br />

Strategic Advice: When you come upon absolute value<br />

questions, one great immediate reaction is to think, "Every<br />

positive number is <strong>the</strong> absolute value of two numbers: <strong>the</strong><br />

number itself and <strong>the</strong> negative of <strong>the</strong> number."<br />

Getting to <strong>the</strong> Answer:<br />

Call <strong>the</strong> integer n. If <strong>the</strong> absolute value of n is between 3<br />

and 6, n must be -5, -4, 4, or 5. Two less than each of<br />

<strong>the</strong>se would be (A), (B), (C), and (D), respectively.<br />

10. B<br />

Difficulty: Medium<br />

Strategic Advice: This problem tests your ability to read<br />

instructions and per<strong>for</strong>m calculations carefully. Follow each<br />

step of <strong>the</strong> procedure in order and avoid careless errors to<br />

find <strong>the</strong> answer.<br />

Getting to <strong>the</strong> Answer:<br />

0.62(20) = 12.4<br />

The largest integer less than 12.4 is 12.<br />

12-4=8<br />

11. D<br />

Difficulty: Medium<br />

Strategic Advice: Follow <strong>the</strong> steps <strong>for</strong> <strong>the</strong> smallest and<br />

largest numbers that can be selected in step 1 to find <strong>the</strong><br />

smallest and largest numbers than can be written in step 5.<br />

This range includes all possible numbers you can write<br />

down in step 5. Numbers outside that range, <strong>the</strong>re<strong>for</strong>e, are<br />

not correct.<br />

Getting to <strong>the</strong> Answer:<br />

Lower bound:<br />

0.5(20) = 10<br />

10 is <strong>the</strong> largest integer less than or equal to 10.<br />

10-4=6<br />

Upper bound:<br />

0.99(20) = 19.8<br />

19 is <strong>the</strong> largest integer less than or equal to 1 9.8.<br />

19-4=15<br />

There<strong>for</strong>e, <strong>the</strong> only numbers that could be written in step 5<br />

are <strong>the</strong> integers between 6 and 15. 0 and 5 are too small,<br />

7.4 is not an integer, and 17 is too large.<br />

12. c<br />

Difficulty: Medium<br />

Strategic Advice: Think about what is happening at each<br />

step. What kind of change does each step make to <strong>the</strong><br />

number? It may be helpful to pick a few sample numbers to<br />

see what happens.<br />

Getting to <strong>the</strong> Answer:<br />

It does not matter whe<strong>the</strong>r you find <strong>the</strong> greatest integer<br />

less than or equal to <strong>the</strong> number and <strong>the</strong>n subtract 4 or<br />

you subtract 4 from <strong>the</strong> number and <strong>the</strong>n find <strong>the</strong> greatest<br />

lower integer. Ei<strong>the</strong>r order produces <strong>the</strong> same number in<br />

step 5.<br />

13. E<br />

Difficulty: Medium<br />

Strategic Advice: Remember <strong>the</strong> rules of multiplying<br />

exponents and raising numbers with exponents to powers.<br />

Plug 33 into each answer choice and see which one<br />

equals 38.<br />

Getting to <strong>the</strong> Answer:<br />

(E) 9(33)2 = 9(33 x 2) = 9(36 ) = 32(36 ) = 32 + 6 = 3s<br />

14. A<br />

Difficulty: High<br />

To find <strong>the</strong> area, add <strong>the</strong> dimensions of <strong>the</strong> square and <strong>the</strong><br />

triangle. First relabel <strong>the</strong> diagram as follows:<br />

12 12 13<br />

b-x<br />

Notice that <strong>the</strong> value of x can be solved with or without<br />

using <strong>the</strong> Pythagorean <strong>the</strong>orem. (The group 5-12-13 is a<br />

Pythagorean triple.)<br />

x2 = 132 - 122 = 169 - 144 = 25, so x = 5<br />

x

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