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

12 Practice Tests for the SAT
81 2 Practice Test Nine Answers and Explanations
You could also have done this by finding the difference of
the percents first. Since 75 percent are full-time and
25 percent are part-time, and since these are percents of
the same whole, the difference between them is just
75% - 25% = 50%. 50% of 800 is 400, again (D).
5. A
Difficulty: Medium
Strategic Advice: Now you have to figure out what percent
of the employees work in the manufacturing department.
What makes this hard is that there are two kinds of
employees-part-time and full-time-and two kinds of
graphs that represent them. You'll have to figure out the
number of part-timers in manufacturing and the number
of full-timers in manufacturing separately. You'll then add
those two amounts together and figure out what percent of
the total that number represents.
Getting to the Answer:
First, find the number of full-time employees in manufacturing.
That's easy-you can just read that off the bar graph,
which tells you that there are 240 full-time employees in
manufacturing. Now for the part-timers. The pie wedge
that says "manufacturing" also says "10%." But 10 percent
of what? Be careful here-it's not 10 percent of the total
number of part-timers; it's 1 0 percent of the total number
of workers, or 10 percent of 800, which is 80. So there are
80 part-timers and 240 full-timers in manufacturing, for a
total of 320 workers in manufacturing. Since there are 800
workers total, the percent is just g, or 16 ° , or 40%, (A).
0
6. B
Difficulty: Low
Strategic Advice: Be careful when you translate English
to math.
Getting to the Answer:
Maurice starts out with $80. He spends $32.45 on clothes,
so after he buys the clothes, he has $80 - $32.45 = $47.55
left. Then he gives $27.55 to his sister, so he has $47.55 -
$27.55 = $20.00 left. You need to find what fraction of the
original $80 he still has, or what fraction of $80 is the $20
he has left. That fraction is just g, or{, (B).
7. E
Difficulty: Medium
Strategic Advice: In this question, you don't have to solve
for x, so if you solved for x, and then plugged one or both of
the values back into the expression 2x2 - 8x, you did a lot
of unnecessary work. If you're given an algebra problem that
you're not solving for the value of one variable, you should
always look carefully at the expression you're solving for.
Can you see any similarities between the expression you're
solving for and the information you're given?
Getting to the Answer:
In this problem, you should have noticed that 2x2 - 8x looks
very similar to x2 - 4x. In fact, you can {odor out a 2: 2x2 -
8x = 2(x2 - 4x). So, if x2 - 4x - 12 = 0, then x2 - 4x = 12,
and 2x2 - 8x= 2(x2 - 4x) = 2(12), or 24, (E).
8. E
Difficulty: Medium
Strategic Advice: Don't be scared by the term "factor-rich."
It's just a made-up expression that is defined by concepts
that you already know. The question tells you that all it
means for a number to be factor-rich is that when you add
up all the {odors of the number, except for the number
itself, that sum is greater than the number. All you have to
do is go through the answer choices and add up the factors
of each one except for the number itself.
Getting to the Answer:
The factors of 6 are l, 2, 3, and 6; adding all of them except
6 gives us l + 2 + 3 = 6. The result is not greater than 6, so
6 is not factor-rich. For (B), you add l + 2 + 4 = 7, which
is not greater than 8. Choice (C) is 9, so you add 1 + 3 =
4. No good. The factors of l 0 are l, 2, 5, and l 0, and l +
2 + 5 = 8, so l 0 is not factor-rich either. Since you're left
with only one answer choice, (E), it must be correct, but just
to check, add up l + 2 + 3 + 4 + 6 = 16, which is indeed
greater than 12, so (E) is correct.
9. D
Difficulty: Medium
Strategic Advice: In this question, you have two parallel
lines, .e 1 and .€ 2
, and two lines that cross both of them,
.€ 3 and .€ 4 . Forget about .€ 3 for a minute and look at what
happens where .€ 4 crosses .e1 and .€ 2
.