Sat 2015 Practice Test #1 Answer Explanations

Choice A is correct.
The total cost 
C
of renting a boat is the sum of the 
initial cost to rent the boat plus the product of the cost per hour and 
the number of hours, 
h
, that the boat is rented. The 
C
-intercept is the 
point on the 
C
-axis where 
h
, the number of hours the boat is rented, is 
7KHUHIRUHWKH
C
-intercept is the initial cost of renting the boat. 
Choice B is incorrect because the graph represents the cost of renting 
only one boat. Choice C is incorrect because the total number of hours 
of rental is represented by 
h-
values, each of which corresponds to the 
ƮUVWFRRUGLQDWHRIDSRLQWRQWKHJUDSKQRWWKH
C
-intercept of the graph. 
Choice D is incorrect because the increase in cost for each additional 
hour is given by the slope of the line, not by the 
C
-intercept. 

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QUESTION 16 
Choice C is correct.
If 
P
is the slope and 
E
is the 
C
-intercept of 
the line, the relationship between 
h
and 
C
can be represented by 
C
= 
PK
+ 
E
. The 
C
LQWHUFHSWRIWKHOLQHLV6LQFHWKHSRLQWVDQG
(1, 8) lie on the line, the slope of the line is
ơ
_
= 
_ 
1
7KHUHIRUH
ơ
the relationship between 
h
and 
C
can be represented by 
C
h
+ 5, the 
slope-intercept equation of the line. 
Choices A and D are incorrect because each of these equations 
UHSUHVHQWVDOLQHWKDWSDVVHVWKURXJKWKHRULJLQ+RZHYHU
C 
is not equal to zero when 
h
&KRLFH%LVLQFRUUHFWDQGPD\UHVXOW
from errors made when reading the scale on each axis as related to 
calculating the slope. 
QUESTION 17