Correct Option: A
| (A + B)’s 1 day’s work = | 1 | |
| 8 |
| (B + C)’s 1 day’s work = | 1 | |
| 24 |
| (C + A)’s 1 day’s work = | 7 | |
| 60 |
On adding all three,
| 2 (A + B + C)’s 1 day’s work = | 1 | + | 1 | + | 7 |
8 | 24 | 60 |
| 2 (A + B + C)’s 1 day’s work = | 15 + 5 + 14 | = | 34 | |
120 | 120 |
| ∴ (A + B + C)’s 1 day’s work = | 17 | |
| 120 |
| ∴ C’s 1 day’s work = | 17 | - | 1 | |
120 | 8 |
| C’s 1 day’s work = | 17 - 15 | = | 1 | |
120 | 60 |
∴ C alone will complete the work in 60 days.
Second method to solve this question ,Here , x = 8 , y = 24 , z = 60/7
| C alone can do in = | 2xyz | |
| xy - yz + zx |
| C alone can do in = | 2 × 8 × 24 × | 60 | |
| 7 |
|
| 8 × 24 - 24 × | 60 | + | 60 | × 8 |
| 7 | 7 |
| C alone can do in = | | 23040 | |
| 7 |
|
| 192 - | 1440 | + | 480 | |
| 7 | 7 |
| C alone can do in = | 23040 | |
| 7 |
|
| 1344 - 1440 + 480 | |
| 7 |
| C alone can do in = | 23040 | × | 7 | = 60 days |
7 | 384 |
