ramu and balu can paint a house in 20 days . ramu alone can do it in 30 days . In how many days can balu alone do it ?
Answers
Ramu and balu can do in 20 days together
Let Ramu can do the work in x days
1 work x days
1 day. 1/x work
Ramu works for 20 days with balu
20 days. 20/x work
Let balu can do the work in y days alone
1 work. y days
1 day. 1/y work
Balu works for 20 days with ramu
20 days. 20/y work
20/x + 20/y =1work
It is given Ramu can do the work alone in 30 days
20/30 + 20/y = 1
20/y =1-20/30
20/y =10/30
20/y =1/3
y =60
In 60 days balu can do it alone
No. of days taken by Ramu alone to do the work=30
Work done by Ramu in a day=1/30
No. of days taken by Ramu and Balu together=20
Work done by Ramu and Balu in a day=1/20
Work done by Balu alone in a day=
Work done by them together in a day - Work done by Ramu alone in a day
1/20-1/30----------->3-2/60---------->1/60
Work done by Balu alone in a day=1/60
No. of days taken by Balu alone=60 days.