A, B and ,C can do a piece of work in 15, 12 and 20 days respectively they started work together but C left after two days. in how many days will be remaining work be completed by A and B
Answers
Answer:
Work is done by A in one day = 1/15
By B = 1/12, and
By C = 1/20
Together (A+B+C) in 1 Day = 1/15+1/12+1/20 = 12/60 = 1/5
2 days work = 2/5
Remaining work = 1-2/5 = 3/5
One day work of A and B = A+B = 1/15+1/12 = 9/ 60 = 3/20
( A+B) work for t days,
3/20t =3/5
t = 4 days
Hence, A and B will complete the work in 4 days
A can finish the work in 15 days
so A can do in one day 1/15 part of the work
similarly
B in one day can do 1/12 part of the work
C in one day can do 1/20 part of the work
In one day
A+B+C = 1/12 +1/15+1/20 = 1/5 work
work done by all 3 in 2 days =2×⅕= 2/5
remaining work = 1-⅖ =⅗
In one day
A+B = 1/15+1/12 = 3/20 part of the work
no. of days taken by A+B to finish ⅗ of the work
=20/3 ×⅗ =4 days