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A and B can do a piece of work in 72 days, B and C can do it in 120 days, and A and C can do it in 90 days. When A, B and C work together, how much work is finished by them in 3 days.
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1 40 -
1 30 -
1 20 -
1 10
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Correct Option: C
Using basics of Rule 5,
| (A + B)’s 1 day’s work = | 72 |
| (B + C)’s 1 day’s work = | 120 |
| (C + A)’s 1 day’s work = | 90 |
On adding all three,
2 (A + B + C)’s 1 day’s work,
| = | + | + | ||||
| 72 | 120 | 90 |
| = | = | |||
| 360 | 30 |
∴ (A + B + C)’s 1 day’s work
| = | 60 |
∴ (A + B + C)’s 3 days’ work
| = | = | |||
| 60 | 20 |
