Question

The length of a rectangle is 10cm and breadth 6cm. If the length is decreased by 3cm and breadth by 2cm. The decrease in the area is

• A. $36c{m}^2$
• B. $32c{m}^2$
• C. $40c{m}^2$
• D. $34c{m}^2$

Answer 1

The correct option is B

$32c{m}^2$

Let ABCD be the rectangle with AB = 10cm and CB = 6cm.

Let length and breadth be decreased by 3 cm and 2 cm respectively as shown.

Area of original rectangle ABCD $=10\times 6c{m}^2$

Area of new rectangle $AEFC=(6-2)\times (10-3)$ = $4\times 7c{m}^2$

Area of AEFC = area ABCD - area EBIF - area HFGD - area FICG

$=10\times 6-4\times 3-2\times 7-3\times 2$

$=10\times 6-12-14-6$

$=10\times 6-\left(32\right)$

Decrease in area = $32c{m}^2$