In a mixture 25 litres, the ratio of milk and water is 4:1. How many litres of milk must be added to make the ratio 16:1?

If the number x3339 is divisible by 11, what is the face value of x?

Vishal sells a bag at a profit of 40%. If Vishal's profit is ₹880, then what is the cost price of the bag?

If 20 women can lay a road of length 100m in 10 days. 10 women can lay the same road of length 50m in: 

Rahim bought a T.V. with 20% discount on list price. Had he bought it with 25% discount he would have saved ₹ 500. At what price did he buy the T.V?  

If $$ a={{\sqrt{3}+\sqrt{2}}\over {\sqrt{3}-\sqrt{2}}}$$ and $$ b={{\sqrt{3}-\sqrt{2}}\over {\sqrt{3}+\sqrt{2}}}$$, then find the value  of $$ {a^2\over b}+{b^2\over a}=?$$

If x+ y=90°, then what is  the value of $$ {\sqrt{cosx.cosecy-cosx.siny}}$$?

The ratio of the square of volume of two cylinders is a:b and the ratio of their radius is x:y, then what is the ratio of their heights?