SAT试题类型 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%

答案：D

解析：

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 .