Question

Ram & Shyam do a work in 10 days. Shyam & Mohan do it in 15 days while Mohan and Ram can do it in 20 days. Find how much time will Mohan take to do it?

Answer 1

ram =x

shyam=y

Mohan=z

x+y=10,x=10-y

y+z=15,z=15-y

x+z=20

10-y+15-y=20

25-2y=20

5=2y

y=2.5

Mohan=15-2.5

= 12.5