The question is - A grocer purchased 200kg of rice at Rs. 25 per kg. He sold 80kg of at a gain of 10% and 40kg at a loss of 4%. At what rate per kg should he sell the remainder to gain 8% on his total investment?

Total CP of 200kg at Rs.25 per kg = 200 × 25

The selling price of 80kg rice at 10% gain

Percentage gain per kg

Percentage gain per kg = 27.5

Percentage gain of 80kg rice = 80 × 27.5

Percentage gain of 80 kg rice = 2200

Selling price of 40kg rice at 4% loss

= Rs. 24 per kg

Loss through out 40 kg = 40 × 24

= 960

Remaining quantity

= 200 – 80 – 40

= 80kg

Total gain required = 8%

Earned Money

= 5400

Money to be earned through the sale of remaining 80kg

= 5400 – 2200 – 960

= 2240

Selling price of the remaining rice

= Rs. 28 per kg