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?

The average age of 32 boys of a class is equal to 15 years. When the age of the class teacher is included the average becomes 16 years. Find the age of the class teacher. 

Directions: The bar graph given below shows the production (in ' 000 tones) of rice of a country for the year 2007 to 2011. Study the graph carefully and answer the question given below it.

The production of rice in the year 2011 is what percent of the production of rice in 2010?

Pooja wants to sell a watch at a profit of 20%. She bought it at 10% less and sold it at ₹ 30 less, but still she gained 20%. The cost price of watch is

The total surface area of a cube is 864 square cm. What will be its volume?

What will be come in place of question mark(?) in the following number series?
8,  14, 25, 46, 82 , ?

The monthly income of a person was ₹ 13,500 and his monthly expenditure was ₹ 9,000. Next year his income increased by 14% and his expenditure increased by 7%. The per cent increase in his savings was  

If $$ {x^4}+{1\over{x^4}}$$ then find $$ {x^3}-{1\over{x^3}}=?$$