Question

A grocer purchased 200 kg of rice at 25 rupees per kg he sold 80 kg of it at a gain of 10% and 40 kg at a loss of 4% at what rate per kg should he sell the reminder to gain 8% on his total investment

Answer 1

Purchase cost = 200 * 25 = Rs 5,000 

Selling price of 80 kg rice - at 10% gain => 110% of price  => (110/100) * Rs 25.
So money earned by selling 80 kg rice = 80 * 110/100 * 25 = Rs 2,200

Selling price of 40 kg rice -- at a loss of 4% => 96% of price => 96/100 *Rs 25
Money earned by selling 40 kg = 40 * 96/100 * 25 = Rs 960

Remaining quantity = 200 - 40 -80 = 80 kg

Total gain required = 8%  =>
Overall money to be earned thru sales = 108/100 * cost = 108/100 * 5,000
            = Rs 5,400

Money to be earned through sale of remaining 80 kg
       = Rs 5,400 - Rs 2,200 - Rs 960 = Rs 2,240

Selling price of the remainder rice = Rs 2,240 / 80 kg = Rs 28/kg