If the length is increased by 25%, by what percent the width of a rectangle should be decreased so as to keep the area same. Choose the correct answer.
A) 25%
B) 20%
C) 30%
D) 10%
E) 15%
SOLUTION :   Let the original length be l and the width be b   Therefore, the area = l*b   Now, as the length is increased by 25%, the new length is (1.25*l) and let the new width be x.   As the area is same, 1.25*l*x = l*b   x = b/1.25 = 0.8b   Therefore, the width is to be decreased by 20%.   ANSWER IS 20%
<result>B</result>
If the length is increased by 25%, by what percent the width of a rectangle should be decreased so as to keep the area same.