He can make 3 pieces. Since he has 8/10 of a candy bar, it is then simplified to 4/5 of a candy bar. You need to find 1/3 of that, that is 4/15. Then how many times does 4/15 fit into 4/5, well simply do this: (4/15)x=4/5. Solving for x should give you 3.
