1/15 + 1/25 = 8/75
75/8 = 9 3/8 days
Anil can do a work in 15 days while Sunil can do it in 25 days. How long will they take if both work together?

a) 3 4/9 days
b) 8 4/9 days
c) 9 3/8 days
d) 6 3/8 days
e) none of these