If price of rice is increased by 25 percent, then by what percentage consumption of rice should be decreased so that the expenditure incurred on rice gets decreased by 40 percent?

52 percent

25% = \(\frac{1}{4}\) , 40% = \(\frac{2}{5}\)

Price                   4   :   5

consumption       a   :    b

Expenditure        5    :   3

{ Expenditure = Price × Consumption }

\(\frac{4a}{5b}\) = \(\frac{5}{3}\)

\(\frac{a}{b}\) = \(\frac{25}{12}\)

Decrease in consumption = 25 - 12 = 13

Decrease percentage  in consumption = \(\frac{13}{25}\) × 100 = 52%