RRB NTPC · Question 72
A and B can complete a job in 40 days and 60 days respectively. They work together for some days and B leaves the job. If A completes the rest of the work in 10 days, find for how many days B worked.
Show answer & explanation
Answer: (B) 18 days
Explanation
If B worked d days, A worked d + 10 days: d/60 + (d + 10)/40 = 1. Multiplying by 120: 2d + 3d + 30 = 120, so d = 18.