A can do a work in $$7\frac{1}{2}$$ hours and B can do the same work in $$10\frac{1}{2}$$ hours. If they work together for $$3\frac{1}{2}$$ hours, then what part of the work will be left out?

A

$$\frac{3}{5}$$

B

$$\frac{4}{5}$$

C

$$\frac{1}{5}$$

D

$$\frac{2}{5}$$