The price of cooking oil increased by 25%. Find by how much percentage a family must reduce its consumption in order to maintain the same budget?

20%

25% = \(\frac{1 }{4}\)

Ratio                     Initial           :               Final

Price                        4               :                 5

Consumption             5              :                   4

{ Price ∝ \(\frac{1}{Consumption}\) }

Required Percentage = \(\frac{5 - 4 }{5}\) × 100 = 20%