Question

A is 4 times more efficient than B, C takes twice
as many days as B to do a piece of work.If A can
finish a job in 12 days. In how many days can A, B
and C working together do the same job?​

Answer 1

Step-by-step explanation:

your answer is there in the figure

Answer 2

Answer:

96/11 days or 8.73 days (approx)

Step-by-step explanation:

A can finish the job in 12 days.

A is 4 times more efficient than B, which means:

B can finish the job in 48 days        (A is four times faster!)

C takes twice as many days as B, which means:

C can finish the job in 96 days

Thus, in one day:

A can finish 1/12 of the job

B can finish 1/48 of the job

C can finish 1/96 of the job

Working together, A, B and C can finish:

1/12 + 1/48 + 1/96 of the job in one day.

1/12 + 1/48 + 1/96 = 8/96 + 2/96 + 1/96 = 11/96

Thus, A, B and C working together can finish 11/96 of the job, in one day.

Hence, the number of days that A, B and C will take to finish the job is 1/(11/96) = 96/11 days = 8.73 days (approx)

(If a person finishes 1/n of the job in one day, he will take n days to finish the  job. 1/(1/n) = n days. This means reciprocal of fraction of work completed in ONE day gives the number of days to finish the full work.)