A can do a work in 60 days. He works for 15 days and later B alone completes the work in 30 days. In what time will they together complete the work?	Select:
A) 24 days
B) 25 days
C) 30 days
D) 32 days
E) none of these

Rationale: let a can do a work in = 1 / 60 days he does 15 days so work done by a in 15 days = ( 15 ) * ( 1 / 60 ) = 1 / 4 remaining work is = 1 - 1 / 4 = 3 / 4 b ' s one day work is = 1 / 30 so 3 / 4 work is done by b in = ( 3 / 4 ) * ( 1 / 30 ) = 1 / 40 days time require to complete the work is = 1 / 60 + 1 / 40 = 5 / 120 5 / 120 = 1 / 24 so 24 days require to complete the work together . answer : a
Answer: A