SSC CHSL Model Paper 13

Let price of sugar = Rs. 100/kg
Expenditure = Rs. 100
New price of sugar = 100 + 18 = Rs. 118
New expenditure = 100+ 12 = Rs. 112
Quantity of sugar bought for Rs. 112 $=\frac{112}{118}\mathrm{kg}$
Required percent decrease $=\frac{1-\frac{112}{118}}{1}\times 100$
$=\frac{118-112}{118}\times 100$ $=\frac{6}{118}\times 100\sim 5.1\%$