Who has appointed DFCCIL as its director finance?

A and B can do a piece of work in 20 days and 12 days respectively. A started the work alone and then after 4 days B joined him till the completion of the work. How long did the work last?

The sum of length, breadth and height of a cuboid is 25 cm. The length of its diagonal is 15 cm. Find the total surface area of the cuboid.

The difference between simple interest and compound interest on a certain sum at $$ 12{1\over2}$$ % for 3 years is Rs 125. Find the sum.

A men sells his cycle at 6% profit. Had he sold it at 15% profit, he would have received 180 Rs. More. What is the cost price of the cycle?

A cask contains 24 litre mixture of wine and water in the ratio 3 : 1. How much mixture must be drawn off and replaced with water so that the quantity of wine and water becomes equal ? 

Three containers contain mixture of milk and water in the ratio 5 : 3,2 : 1 and 7 : 5 respectively . The measurement of containers are in the ratio 4 : 5 : 6. Mixture of all the containers are mixed to get a new mixture . Find the ratio of water and milk in the new mixture . 

Two numbers are in the ratio x : y . If 2 is added to both numerator and denominator ,  the fraction becomes $$ 1\over2$$. Find the value of x + y .