The ratio of the volume of two right circular cylinder is 2 : 3. And the ratio of their radius is 1 : 2. Find the ratio of their heights?

A , B, and C together can finish a task in 12 days. A is twice as productive as B and C alone can do the task in 36 days. In how many days can A and B do the task if C goes on leave? 

The average of all the numbers between 6 and 50 which are divisible by 5 is

If * means adding 6 times the second number to the first number then ( 1 * 2 ) *   3 equals : 

$$3\sqrt{ {72.9\over0.4096}}$$ is equal to : 

Some litres of acid were drawn off a 54-litre vessel full of acid and an equal amount of water added. Again, the same volume of the mixture was drawn off and replaced by water. As a result, the vessel contained 24 litre of pure acid. How much of the acid was drawn off initially?

Kuldeep sells an article for ₹ 3240 and earns a profit of 20%. What is the cost price of the article?

The price of 6 pencils is Rs. 30 and that of 12 pens is Rs. 120. What is the average price of 50 pencils and 50 pens?