यदि 5 पंप प्रतिदिन 8 घंटे काम करके एक जलाशय को 30 दिनों में खाली कर सकते हैं, तो प्रतिदिन 6 घंटे काम करने वाले 4 पंप उसी जलाशय को कितने दिनों में खाली कर सकते हैं?

If P and Q together can complete a piece of work in 15 days and P alone can do it in 45 days, in how many days can Q alone complete that work?

A can lay a railway track between two stations in 16 days and B can do the same job in 12 days. With the help of C, they finished the job in 4 days. In how many days can C alone do the job?