Question

1. A can do a piece of work in 10 days, B can do the same work in 20 days, with the help
of C, they finished the work in 4 days. In how many days C can do the work in alone​

Answer 1

Answer:

C can do the work alone in 10 days

Step-by-step explanation:

for convenience we divide the piece of work in 20 parts

According to this,

A's rate of doing work = 2 parts/day

B's rate of doing work = 1 part/day

Let C's rate of doing work = x parts/day

All of them finished the work in 4 days

so the combined rate of doing work = 20 parts / 4 days

                                                             = 5 parts/day

combined rate = A' rate + B's rate + C's rate

5 = 2 + 1 + x

x= 2 parts/day

time taken by c to finish the work alone= 20 parts / 2 parts/day

                                                                 = 10 days