Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
The length of a rectangle is increased by 20%, and the width of the rectangle is increased by 30%. By what percentage will the area of the rectangle be increased?
(A) 25%
(B) 36%
(C) 50%
(D) 56%
(E) 60%
The Correct answer is D.
Explanation
Let 
and 
be the original length and width of the rectangle, respectively. If we denote by 
and 
the new length and width of the rectangle, respectively, then we have:
and 
So, the new area will be:
where (
) is the original area of the rectangle.
So the area is increased by 
.
