Wheat is now being sold at ₹ 27 per kg. During last month, its cost was ₹ 24 per kg. Find by how much per cent a family reduced its consumption, so as to keep the expenditure fixed.

Old price of rice = ₹ 24/kg
New price of rice = ₹ 27 per/Kg
∴ increased in price of rice = New price - Old prices = 27 - 24 = ₹ 3/kg
∴ increased percentage in price = (3/24) x 100
= 12¹/₂ %
Now, reduction in consumption, so as to keep the expenditure fixed.
According to the formula,
= [a/(100 + a)] x 100 %
=[1.25/(100 +12.5)] x 100%
= 11.1%