Question 57

The length and breadth of a rectangle are 20 m and 15 m respectively. If length is Increased by 20% and the breadth by 30%, the percentage increase in its area is

Solution

Length of rectangle = $$l=20$$ m and Breadth = $$b=15$$ m

=> Area = $$A=l\times b=(20\times15)=300$$ $$m^2$$

Similarly, new length = $$l'=20+(\frac{20}{100}\times20)=20+4=24$$ m

=> New breadth = $$b'=15+(\frac{30}{100}\times15)=15+4.5=19.5$$ m

New area = $$A'=24\times19.5=468$$ $$m^2$$

$$\therefore$$ Increase in area = $$\frac{(468-300)}{300}\times100$$

= $$\frac{168}{3}=56\%$$

=> Ans - (B)

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