Question

A and B can do a job in 18 days. If A is thrice as efficient as B, in how many days
will A finish the job, working alone?​

Answer 1

18 * 3 so it can be anything

Answer 2

A alone can finish the work in 24 days

1) Let time taken by A alone is x days.

2) Since, A is three times efficient than B, time taken by B would be 3x days.

3) If they work together, they finish work in 18 days.

4) Work done by A in on day = 1/x

5) work done by B in one day = 1/3x.

6) Total work done by them in one day would be 1/x+ 1/3x = 4/3x

7) Time taken to complete the work together is 3x/4.

8) Equating, 3x/4 = 18.

9) x = 24 days