If each side of a rectangle is decreased by 11%, then its area will decrease by :
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 20.79%
Let the length and breadth of a rectangle be l and b.
The new length = l - 11% of l = l - 0.11l = 0.89l
The new breadth = b - 11% of b = b - 0.11b = 0.89b.
Decrease in area = 1lb - (0.89l × 0.89b) = 1lb - 0.7921lb = 0.2079lb
Percentage decrease in area = (0.2079lb × 100)/lb = 20.79%