Quantity I: The price of rice is decreased by 30%, by how much % the consumption is increase so that the expenditure will decreased by 10%? Quantity II: A man spends Rs. 45,600 out of his income 68,400. If his income and expenditure are increased by 19% and 13%. Find the percentage change in his savings.

Quantity I: Total Expense = Price per unit Consumption So let Price per unit & consumption both are 100 So toal expense = 100   100 = Rs. 10000 New total expense = 10000   0.90 = Rs. 9000 & New price per unit = Rs. 100   0.7 = 70    So New Total Expense = New Price per unit     New Consumption 9000 = 70     new consumption So new consumption = 9000/70 = 900/7 Hence ratio of old & new consumption = 100 : 900/7  =  700 : 900 =  7 : 9 Hence increase in comsumption  = (9-7) /7   100 = 28.56% Quantity II: Expense / Income = 45600/68400 = 2/3   Hence Let orginal income = 300 & original expense = 200 So saving = 300 - 200  = 100   Now new income = 300  119% = 357 , New expense = 200   113% = 226, So new saving = 357 -226 = 131   Hence change in saving % = (131-100)/100   100 = 31% So Quantity I < Quantity II