A shopkeeper buys mangoes at the rate of 4 a rupee and sells them at 3 a rupee. Find his net profit or loss percent?

A. 20%
B. 28%
C. 33 1/3 %
D. 35 2/7 %
Explanation:
The total number of mangoes bought by the shopkeeper be 12.
If he buys 4 a rupee, his CP = 3
He selling at 3 a rupee, his SP = 4
Profit = SP – CP = 4 – 3 = 1
Profit Percent = 1/3 * 100 = 33 1/3 %