Question

A, B, C can do a job in 10, 20 and 40 days respectively. In how many days A can complete the job if he is assisted by
B and C on every third day
a
7 days
6 days
9 days
8 days
​

Answer 1

Answer:

Step-by-step explanation:

ans 9 days

Answer 2

Concept Introduction:

Efficiency of doing a work is inversely proportional to time taken.

Given: A, B, C can do a job in $10, 20$ and $40$ days respectively.

To Find:

We have to find the value of, days A can complete the job if he is assisted by B and C on every third day.

Solution:

According to the problem,

A can do $1/10$ of work in one day.

B can do $1/20$ of work in one day.

C can do $1/40$ of work in one day.

Total work is to be $1$.

$1/10+1/10+(1/10+1/20+1/40)+1/10+1/10+(1/10+1/20+1/40)+1/10+1/10+1/10=7/10+7/20=21/20$

On last day A,B,C don't have to work fully hence total $9$ days are required to complete the work.

Final Answer:

The value of number of days to complete the is $9$ days.

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