Question:
A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
[A].12 days
15 days
16 days
18 days
A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
| A’s 2 day’s work = | 1 | x 2 | = | 1 | . | ||
| 20 | 10 |
| (A + B + C)’s 1 day’s work = | 1 | + | 1 | + | 1 | = | 6 | = | 1 | . | ||
| 20 | 30 | 60 | 60 | 10 |
| Work done in 3 days = | 1 | + | 1 | = | 1 | . | ||
| 10 | 10 | 5 |
| Now, | 1 | work is done in 3 days. |
| 5 |
Whole work will be done in (3 x 5) = 15 days.