Question

Aye work is done by a in 80 Days if the same work is completed by a in 10 days and the remaining work is done by b in 42 days finally what is the time taken to complete the work by both a and b

Answer 1

work done by a in 10 days= 10/80 = 1/8
remaining work= 7/8

B takes 42 days for 7/8 work
so B can alone = 8/7×42 = 48days

a and b can do in a×b/a+b= 80×48/128= 30 days.