Correct Option: C
| (A + B)’s 1 day’s work = | 1 | |
10 |
| (B + C)’s 1 day’s work = | 1 | |
6 |
| (C + A)’s 1 day’s work = | 1 | |
12 |
Adding all three ,
| 2 (A + B + C)’s 1 day’s work = | 1 | + | 1 | + | 1 |
10 | 6 | 12 |
| 2 (A + B + C)’s 1 day’s work = | 6 + 10 + 5 | |
60 |
| 2 (A + B + C)’s 1 day’s work = | 21 | = | 7 | |
60 | 20 |
| ∴ (A + B + C)’s 1 day’s work = | 7 | |
40 |
| ∴ All three together will complete the work in = | 40 | = 5 | 5 | |
7 | 7 |
Second method to solve this question ,Here , x = 10 , y = 6 , z = 12
| Time taken = | 2 × 10 × 6 × 12 | = | 1440 | |
10 × 6 + 6 × 12 + 12 × 10 | 60 + 72 + 120 |
| Time taken = | 1440 | = | 40 | |
252 | 7 |
