Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
Milk costs X cents per half-gallon and Y cents per gallon. If a gallon of milk costs Z cents less than 2 half-gallons, which of the following equations must be true?
(A) 
(B) 
(C) 
(D) 
(E) 
The Correct answer is C.
Explanation
The cost of a gallon of milk 
is equal to 
cents less than the cost of 
half-gallons 
. This can be written algebraically as 
. Subtracting 
from both sides of the equation yields 
.