2021 · Q70
The ratio between the work done by (x − 1) men in (x + 1) days and the work done by (x + 2) men in (x − 1) days is 9 ∶ 10. What will be the value of x?
Elementary MathematicsTime and Work
- A8
- B9
- C10
- D12
Explanation
Work ∝ men × days, so [(x−1)(x+1)]/[(x+2)(x−1)] = (x+1)/(x+2) = 9/10. Cross-multiplying: 10x + 10 = 9x + 18, so x = 8. Hence option A.