A and B together can complete a piece of work in 15 days. B and C together can do it in 24 days. If A is twice as good a workman as C, then in how many days can B alone complete the work?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e 60 days
| Understanding | Application |
| The rate of efficiency is inversely proportional to the time taken in completing work. |
Time is taken by A & B to complete the work = 15days Let the efficiencies of A & B be 1/A & 1/B respectively. ⇒ 1/A + 1/B = 1/15 Time is taken by B & C to complete the work = 24days Let the efficiency of C be 1/C. ⇒ 1/B + 1/C = 1/24 ⇒ 1/A = 2/C Putting the value in first case ⇒ 1/A + 1/B = 1/15 ...(1) Putting the value in second case ⇒ 1/2A + 1/B = 1/24 ...(2) By solving (1) & (2) we would get ⇒ B = 60 days |