SSC CHSL Model Paper 11

Let price of sugar = Rs. 100/kg
Expenditure = Rs. 100
New price of sugar = 100 + 20 = Rs. 120/kg
New expenditure = Rs. (100 + 8) = Rs. 108
Quantity of sugar bought for Rs. 108 $=\frac{180}{120}\mathrm{kg}$
Required percent decrease in consumption $=\frac{\left(1-\frac{108}{120}\right)}{1}\times 100$ $=\frac{120-108}{120}\times 100=10\%$