If the price of apple increases from Rs. 80 per kg to Rs. 100 per kg, by what per cent a person should decrease the consumption of apple so that his expenditure remains same?

Answer : Option C

Explanation :

Increase in the price of apples = Rs. (100 – 80) = Rs. 20 $\therefore$ Profit per cent $=\frac{20}{80} \times 100=25 \%$ $\therefore$ Required percentage decrease in consumption $=\frac{25}{100+25} \times 100=\frac{25}{125} \times 100=20 \%$ Let

$\therefore$ Required percent decrease $=\frac{20}{100} \times 100=20 \%$