Question 116

If the length of a rectangle is decreased by 20% and breadth is decreased by 40%, then what will be the percentage decrease in the area of the rectangle?

Solution

Let the length and breadth of the rectangle be $$10$$ cm

Area of rectangle = $$10\times10=100$$ $$cm^2$$

After decreasing the length by 20%, => New length = $$10-(\frac{20}{100}\times10)$$

= $$10-2=8$$ cm

Similarly, new breadth = $$10-(\frac{40}{100}\times10)$$

= $$10-4=6$$ cm

=> New area = $$8\times6=48$$ $$cm^2$$

$$\therefore$$ Decrease in area = $$\frac{(100-48)}{100}\times100=52\%$$

=> Ans - (B)

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