Answer:
Ahmed sold (7/10) of a mango
Explanation:
I don't know how one sells 3/10 or 2/5 of a mango, but he will have sold:
3/10 + 2/5
3/10 + (2/5)*(2/2) [Convert the denominator in 2/5 to 10, so that we can add it to 3/10]
3/10 + (4/10)
(7/10) Ahmed sold (7/10) of a mango