Question

If each side of a rectangle is increased by 50 % then its area will be increased by

• A. 150%
• B. 120%
• C. 125%
• D. none of these

Answer 1

The correct option is C 125%

Let sides of rectangle is x cm and y cm

Then area =xy sq cm

If both sides increased 50%

Then side =$x+\frac{50}{100}x=\frac{3x}{2}$

And other side =$y+\frac{50}{100}x=\frac{3y}{2}$

Then area of new triangle =$\frac{3x}{2}\times \frac{3y}{2}=\frac{9xy}{4}$

So increased in area=$\frac{9xy}{4}-xy=\frac{9xy-4xy}{4}=\frac{5xy}{4}$$

So % increased in area =$\frac{\frac{5xy}{4}}{xy}\times 100=125$ %