The price of a commodity is increased by 36% and the quantity purchased is decreased by 30%. What is the percentage increase/decrease in the amount spent on the commodity?

4.8% decrease

                       Earlier        Later

           Price        25     :     34              [36% = \(\frac{9}{25}\)]

         Quantity    10      :      7               [ 30% = \(\frac{3}{10}\)] 

                       ---------------------

Expenditure     250    :    238           [Exp.= Price x Quantity]

Difference = 12R

Effect on Exp. = \(\frac{12}{250}\) × 100 = 4.8% decrease