On increasing the price of T.V. sets by 60%, their sale decreases by 20%. What is the effect on the revenue receipts of the shop ? Choose the correct choice from the following choices.
A) 4 B) 5 C) 56 D) 28 E) 7

Rationale: explanation : let the price be = rs . 100 , and number of units sold = 100 then , sale value = rs . ( 100 × 100 ) = rs . 10000 new sale value = rs . ( 160 × 80 ) = rs . 12800 increase % = 2800 / 10000 × 100 = 28 % answer : d
Answer: D