The cost of apple, banana and mango are 80rs/kg, 50rs/dozen and
40rs/kg.
Following are the discount schemes
1 kg mango free with 5 dozen banana
1 kg apple free with 10 kg mango
Cost of 23 kg mango, 7 kg apple and 15 dozen banana will be
[You have to choose a case with exact amount of all the fruits given above including the fruits in discount]
total purchased fruits
20 kg mango and free 2 kg apple
5 kg apple
15 dozen banana and free 3 kg mango
total cast of purchased fruits = 20*40+5*80+15*50 = 800+400+750 = 1950
remaining fruits are free.