2022 · Q13
X and Y can do a piece of work in 45 days and 40 days respectively. They begin to work together, but X leaves after n days and then Y completes the remaining work in 23 days. What is n equal to?
Elementary MathematicsTime and Work
- A8
- B9
- C10
- D12
Explanation
In n days X and Y together complete n(1/45+1/40) = 17n/360 of the work, and Y alone completes 23/40. So 17n/360 + 23/40 = 1, i.e. 17n/360 = 17/40, giving n = 9. The keyed option is B.