A person buys certain number of marbles at 20 per taka and an equal number at 30 per taka. He mixes them and sells them at 25 per taka. His gain or loss in the transaction is-
সমাধান
সঠিক উত্তর: Option B
Cost price of a each marble at 20 per Tk. = Tk. 1/20
Cost price of a each marble at 30 per Tk. = Tk. 1/30
∴ Average cost of marble = {(1/20) + (1/30)}/2
= (3 + 2)/(2 × 60)
= 5/120
= 1/24
Selling price of mixed marble = Tk. 1/25
∴ Loss = (1/24) - (1/25) = 1/600
Cost price 1/24 then loss Tk. 1/600
Cost price 1 then loss Tk. (1/600)/(1/24)
∴ Cost price 1 then loss Tk. {(1/600)/(1/24)} × 100 = 4%
∴ There is loss of 4%
Cost price of a each marble at 30 per Tk. = Tk. 1/30
∴ Average cost of marble = {(1/20) + (1/30)}/2
= (3 + 2)/(2 × 60)
= 5/120
= 1/24
Selling price of mixed marble = Tk. 1/25
∴ Loss = (1/24) - (1/25) = 1/600
Cost price 1/24 then loss Tk. 1/600
Cost price 1 then loss Tk. (1/600)/(1/24)
∴ Cost price 1 then loss Tk. {(1/600)/(1/24)} × 100 = 4%
∴ There is loss of 4%
