Correct Option: D
| Work done by (A + B) in 1 day = | 1 | |
30 |
| Work done by (B + C) in 1 day = | 1 | |
20 |
| Work done by (C + A) in 1 day = | 1 | |
15 |
On adding,
| Work done by 2 (A +B + C) in 1 day = | 1 | + | 1 | + | 1 |
30 | 20 | 15 |
| Work done by 2 (A +B + C) in 1 day = | 2 + 3 + 4 | |
60 |
| Work done by 2 (A +B + C) in 1 day = | 9 | = | 3 | |
60 | 20 |
| ∴ Work done by (A + B + C) in 1day = | 3 | |
40 |
| ∴ (A + B + C) will do the work in | 40 | = 13 | 1 | days |
3 | 3 |
Second method to solve this question ,Here , x = 30 , y = 20 , z = 15
| Time taken = | 2xyz | |
xy + yz + zx |
| Time taken = | 2 × 30 × 20 × 15 | |
30 × 20 + 20 × 15 + 15 × 30 |
| Time taken = | 18000 | |
600 + 300 + 450 |
| Time taken = | 18000 | = 13 | 1 | days |
1350 | 3 |
