Question

A can finish a work in 24 days, B in 9 days and C in 12 days. B and C together start the work but are forced to leave after 3 days.
What was the time taken by A to finish the remaining work alone?

• A. 5 days
• B. 6 days
• C. 10 days
• D. 13 days
• E. 16 days

Answer 1

The correct option is C

10 days

(B+C)’s 1 day’s work $=(\frac{1}{9}+\frac{1}{12})=\frac{7}{36}$

Work done by B and C in 3 days $=(\frac{7}{36}\times 3)=\frac{7}{12}$

Remaining work = $(1-\frac{7}{12})=\frac{5}{12}$

Now, $\frac{1}{12}$ work is done by A in 1 day.

So, $\frac{5}{12}$ work is done by A in $(24\times \frac{5}{12})=10days$