Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
A mechanic can install carburetors in 3 cars every 4 hours. At that rate, how long will it take the mechanic to install carburetors in 5 cars?
(A) 6 hr 20 min
(B) 6 hr 40 min
(C) 7 hr 15 min
(D) 7 hr 30 min
(E) 7 hr 45 min
The Correct answer is B.
Explanation
From the information given, you can write the proportion 
cars is to 
hours as 
cars is to 
hours, where 
represents the number of hours the mechanic will take to install carburetors in 
cars. This gives 
, which simplifies to 
. Therefore, 
hours. Since 
hour is 
minutes, 
is 
hours 
minutes.