Question

A and B can complete the work in 6 days while A and C can complete the work in 10 days. A, B and C together can complete the work in 5 days. Find the time in which B alone can complete the work.
1. 10 days
2. 16 days
3. 20 days
4. 15 days
5. 30 days

Answer 1

Correct Answer - Option 1 : 10 days

Given:

Time taken by A and B to complete the work = 6 days

Time taken by A and C to complete the work = 10 days

Time taken by A, B and C to complete the work = 5 days

Calculation:

⇒ 1/A  + 1/B  = 1/6

⇒ 1/A + 1/C = 1/10

⇒ 1/A + 1/B + 1/C = 1/5

⇒ 2/A + 1/B + 1/C = 4/15

Solving,

A = 15, B = 1/10 and C = 1/30

∴ B alone can complete the work in 10 days