दो पाइप A और B मिलकर एक टंकी को 4 घंटे में भर सकते हैं। यदि उन्हें अलग-अलग खोला जाता, तो टंकी को भरने में पाइप B को A से 6 घंटे अधिक लगते। A द्वारा अकेले टंकी को भरने में कितना समय लगेगा?

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?