A can do 1/3 of the work in 5 days and B can do 2/5 of the work in 10 days. In how many days both A and B toether can do the work?

Question

( A ) 8 2/3 days
( B ) 9 3/5 days
( C ) 9 3/8 days
( D ) 8 3/5 days