Answer:
about 14.04%
Explanation:
If a loss of 5% on sale of 1/4 of goods purchased for ₹80, you want to know the percentage increase in selling price required for the remainder if an overall gain of 5% is desired.
Unit price
The cost of 1/4 of the goods is (1/4)(₹80) = ₹20. If a loss of 5% was realized, the revenue from the sale was (1 -5%)(₹20) = ₹19. At that rate, the "unit price" for the entire quantity of goods is ...
(₹19)/(1/4) = ₹76
Additional revenue
The desired return of 5% on the original outlay means the man wants a total revenue of ...
(1 +5%)(₹80) = ₹84
On sale of 1/4 units, his revenue was ₹19, so he needs to price the remaining 3/4 to bring in (₹84 -19) = ₹65. The new unit price is then ...
(₹65)/(3/4) = ₹86.67
Percentage change
The increase in price per unit from ₹76 to ₹86.67 represents a percentage increase of ...
(86.67/76 -1) × 100% = (8/57) × 100% ≈ 14.035%
The selling price must be raised by about 14.04%.