A and B are two alloys of gold and copper prepared by mixing metals in the ratio 7 : 2 and 7 : 11 respectively. If equal quantities of alloys are melted to form a third alloy C. Find the ratio of gold and copper in C?

A contractor took to do a piece of work in 150 days. He employed 200 men. After 50 days he found that only 1/4 of the work has been done. How many additional men should be employed so that the work may be completed in time?