Correct Option: B
According to the question ,
| Work done by A and B together in one day = | 1 | part |
10 |
| Work done by B and C together in one day = | 1 | part |
15 |
| Work done by C and A together in one day = | 1 | part |
20 |
So,
Adding I, II, III, we get
| 2 (A + B + C) = | 1 | + | 1 | + | 1 |
10 | 15 | 20 |
| 2 (A + B + C) = | 6 + 4 + 3 | = | 13 | |
60 | 60 |
| A + B + C = | 13 | ....(IV) |
120 |
Putting the value of eqn. (I) in eqn. (IV)
| ∴ Work done in 1 day by C is | 1 | Part |
120 |
Hence, C will finish the whole work in 120 days
Second method to solve this question ,Here , x = 10 , y = 15 , z = 20
| Time Taken by C = | 2xyz | |
xy - yz + zx |
| Time Taken by C = | 2 × 10 × 15 × 20 | |
10 × 15 - 15 × 20 + 20 × 10 |
| Time Taken by C = | 6000 | |
150 - 300 + 200 |
| Time Taken by C = | 6000 | = 120 days |
50 |
