Correct Answer - Option 2 : 72.55%
Given:
Allowing successive discounts of 25% and 15% on the pen gives a net gain of 10% on cost.
Concepts used:
M.P. = S.P. + Discount
Discount % = Discount/M.P. × 100
Gain % = Gain/C.P. × 100
Gain = S.P. – C.P.
Calculation:
Allowing successive discounts of 25% and 15% on the pen gives a net gain of 10% on cost. Let M.P. of article be Rs. x.
⇒ Total discounts = (x/4) + {15% × (x – (x/4))} = 29x/80
⇒ S.P. = M.P. – Total discounts
⇒ S.P. = x – (29x/80) = 51x/80
A net gain of 10% is made on cost.
Gain % = Gain/C.P. × 100
Let C.P. be Rs. y.
⇒ 10 = (51x/80 – y)/y × 100
⇒ 11y/10 = 51x/80
⇒ y = 51x/88
Percentage by which M.P. must be marked over C.P. = {(x – 51x/88)/(51x/88)} × 100 = 72.55%
∴ M.P. must be marked over C.P. by 72.55%.