Sat 2015 Practice Test #1 Answer Explanations

Choice C is correct.
Substituting 6 for 
[
and 24 for 
y
in 
y
= 
N[
gives 
24 = (
k
)(6), which gives 
k
= 4. Hence, 
y
= 4
[
. Therefore, when 
[
= 5, 
the value of 
y
LV 1RQHRIWKHRWKHUFKRLFHVIRU
y
is correct 
because 
y
is a function of 
[
, and so there is only one 
y
-value for a given 
[
-value. 
Choices A, B, and D are incorrect. Choice A is the result of substituting 
6 for 
y
and substituting 5 for 
[
in the equation 
y
= 
N[
, when solving for 
k
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k
and 5 for 
[
in the equation 
y
= 
N[
, when solving for 
y
. Choice D results from using 
y
= 
k
+ 
[
instead 
of 
y
= 
N[
. 

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QUESTION 3 
Choice D is correct.
Consider the measures of 
∠
DQG
∠
LQWKHƮJXUH
below. 
m
1 
2 4 
3 
s
t
The measure of 
∠
LVHTXDOWRWKHPHDVXUHRI
∠
1 because they are 
corresponding angles for the parallel lines 
Ž
and 
P
intersected by the 
transversal line 
t
. Similarly, the measure of 
∠
LVHTXDOWRWKHPHDVXUH
of 
∠
4 because they are corresponding angles for the parallel lines 
V
and 
t
intersected by the transversal line 
P
. Since the measure of 
∠
1 
LVrWKHPHDVXUHVRI
∠
DQG
∠
DUHDOVRr6LQFH
∠
4 and 
∠
2 are 
supplementary angles, the sum of the measures of these two angles is 
r7KHUHIRUHWKHPHDVXUHRI
∠
LVrơr r
&KRLFH$LVLQFRUUHFWEHFDXVHrLVWKHPHDVXUHRI
∠
1, and 
∠
1 is not 
congruent to 
∠
2. Choice B is incorrect because it is the measure of the 
complementary angle of 
∠
1, and 
∠
1 and 
∠
2 are not complementary 
angles. Choice C is incorrect because it is double the measure of 
∠
1, 
which cannot be inferred from the information given. 
48(67,21
Choice C is correct.
The description “16 + 4
[LVPRUHWKDQšFDQ
be written as the equation 16 + 4
[ ZKLFKLVHTXLYDOHQWWR
16 + 4
[
= 24. Subtracting 16 from each side of 16 + 4
[
= 24 gives 4
[
= 8. 
Since 8
[
is 2 times 4
[
, multiplying both sides of 4
[
= 8 by 2 gives 
8
[
= 16. Therefore, the value of 8
[
is 16. 
Choice A is incorrect because it is the value of 
[
, not 8
[
. Choices B and 
D are incorrect and may be the result of errors made when solving the 
equation 16 + 4
[ IRU[
. For example, choice D could be the 
result of subtracting 16 from the left side of the equation and adding 
16 to the right side of the equation 16 + 4
[ JLYLQJ[ 
and 8
[ 
QUESTION 5 
Choice D is correct.
A graph with a strong negative association 
between 
G
and 
t
would have the points on the graph closely aligned 
with a line that has a negative slope. The more closely the points on a 
graph are aligned with a line, the stronger the association between 
G
and 
t
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graphs, the points on graph D are most closely aligned with a line with 
a negative slope. Therefore, the graph in choice D has the strongest 
negative association between 
G
and 
t
. 

---

Choice A is incorrect because the points are more scattered than the 
points in choice D, indicating a weaker negative association between 
G
and 
t
. Choice B is incorrect because the points are aligned to either 
a curve or possibly a line with a small positive slope. Choice C is 
incorrect because the points are aligned to a line with a positive slope, 
indicating a positive association between 
G
and 
t
. 
QUESTION 6