In a market, the price of medium quality mangoes is half that of good mangoes. A shopkeeper buys 80 kg good mangoes and 40 kg medium quality mangoes from the market and then sells all these at a common price which is 10% less than the price at which he bought the good ones. His overall profit is

Correct Option: B

Let the price of good quality mangoes be Rs. 2x per kg.
Then, the price of medium quality mangoes is Rs. x per kg.

The cost price (CP) for 80 kg of good mangoes and 40 kg of medium quality mangoes is:
CP = 80 * 2x + 40 * x = 160x + 40x = 200x

The selling price (SP) of each kg of mango is 10% less than the buying price of good mangoes:
SP per kg = 2x - 10% of 2x = 1.8x

The total quantity of mangoes sold is:
80 kg + 40 kg = 120 kg

Therefore, the total selling price (Total SP) is:
Total SP = 120 * 1.8x = 216x

The overall profit is:
Profit = Total SP - CP = 216x - 200x = 16x

The profit percentage is:
Profit % = $\frac{16x}{200x}\times 100\%=8\%$