Question

A can do a work in 15 days b can do it in 25 days and c can do it in 30 days. How many days will it take if they work together?

Answer 1

When the a b c take work together they take time 20 day

Answer 2

Given :-

(i) A can do work in 15 days.

(ii) B can do work in 25 days.

(iii) C can do work in 30 days.

To find :-

Number of days required when they all work together.

Solution :-

==> Total work = L.C.M of (15,25,30)

==> Total work = 150

Now :-

==> Efficiency of A = Total work /time

==> Efficiency of A = 150/15

==> Efficiency of A = 10

Similarly :-

==> Efficiency of B = 150/25

==> Efficiency of B = 6

And :-

==> Efficiency of C = 150/30

==> Efficiency of C = 5

Now :-

Total time taken by A + B + C = 150/21

Total time taken by A + B + C = 50/7 days

Hence :-

(A+B +C) together will take 50/7 days to finish the work.