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

12 Practice Tests for the SAT /
Practice Test Eight Answers and Explanations
725
SECTION 2
1. A
Difficulty: Low
Strategic Advice: The important thing to remember here
is that when solving an algebraic equation, you have to do
the same thing to both sides of the equation. You're given
an equation with Sx + 3 on the left side of the equal sign,
and the question asks about Sx + 10. To make Sx + 3 look
like Sx + 1 O, just add 7. But since you've added 7 to the left
side of the equation, you have to add 7 to the right side of
the equation also. Adding 7 to the right side of the equation
gives you 21 + 7, or 28, (A).
Getting to the Answer:
A more mathematical way of expressing what you just did is
to write it out like this:
Sx
Sx
2. E
+
+
+
Difficulty: Medium
3
+7
10
Strategic Advice: You have to know a few facts about
geometry and lines and angles. The word bisects means
cuts in half. So, if line EX bisects angle BXD, it cuts angle
BXD into two equal halves. The diagram shows that angle
BXE is 30°, and since it is half of angle BXD, angle BXD must
equal 60°.
Getting to the Answer:
Now that you've found the degree measure of angle BXD,
find the degree measure of angle CXB. Angles CXB and BXD
are supplementary angles because they form line segment
CXO. So angle CXB plus angle BXD equals 1 80°. Since angle
BXD is 60°, angle CXB equals 1 80° - 60° or 120°.
You can eliminate two answer choices by just eyeballing the
figure. Assume that the angle measurement is about what it
looks like. You should know what a 90-degree angle looks
like-the corner of a piece of paper. Angle CXB in the figure
is clearly greater than 90°, so (A) and (B) can be eliminated.
So you could guess among (C), (D), and (E).
21
+7
28
3. D
Difficulty: Low
Strategic Advice: Early questions like this one are not trying
to trick you or test your ability to think critically, but rather
just to be careful in your calculations. Remember this, and
you can rack up easy points on Test Day.
Getting to the Answer:
4. A
b-3c= 5
b - 3(1)= 5
b = 8
a-2b= 10
a - 2(8) = 10
a- 16= 10
Difficulty: Low
a=26
Strategic Advice: As with many word problems, this
question tests your ability to translate words into a formula.
Once you write this formula, the answer should be clear.
Getting to the Answer:
John has more money than Billy, so b