Out of the 10 apples that I had, 25 of them were spoilt. After selling off some of the fresh ones, I was left with 13 of the fresh apples. Half of the remaining apples were eaten up by my friend. Then the number of apples left with me is
1
Total number of apples = 10
Number of apples that were spoilt =10×25= 4 apples
Now, the number of fresh apples left = 6 apples
Number of fresh apples left, after selling some of them = 6×13 = 2 apples.
Since half of the 2 apples is eaten by the friend, the number of apples left = 2×12 = 1 apple
Therefore, only 1 apple is left.