Shortcut Trick Ratio of Income : Expenditure : Savings = 80,000 : 45,000 : 35,000 = 16 : 9 : 7 Total units of Income Increase = 16 × 16% = 256 Total units of Expenditure Increase = 9 × 8% = 72 Total units of Savings Increase = 256 − 72 = 184 Percentage Increase in Savings = 184 ÷ 7 ≈ 26.29% ∴ The correct answer is 26.29%. Alternate Method Given: Monthly Income = ₹80,000, Monthly Expenditure = ₹45,000 Formula Used: Savings = Income − Expenditure; % Increase = (Change ÷ Original) × 100 ⇒ Original Savings = 80,000 − 45,000 = ₹35,000 ⇒ Increase in Income = 16% of 80,000 = ₹12,800 ⇒ Increase in Expenditure = 8% of 45,000 = ₹3,600 ⇒ Increase in Savings = 12,800 − 3,600 = ₹9,200 ⇒ Percentage Increase in Savings = (9,200 ÷ 35,000) × 100 ⇒ % Increase = 920 ÷ 35 ≈ 26.2857% ∴ The correct answer is 26.29%. Related Concepts: Fundamental Income Identity Total Income is always the sum of Expenditure and Savings (I = E + S). Any change in Income must be balanced by changes in E and S. Weighted Average Method Income % change = (Exp Ratio × Exp % change + Savings Ratio × Savings % change) ÷ (Exp Ratio + Savings Ratio). Percentage Change Formula Percentage Change = [(Final Value − Initial Value) ÷ Initial Value] × 100.