Quantitative Aptitude - Arithmetic Ability Questions

The average age of 40 students of a class is 16 years. If the average age of 24 students is 15.5 years and that of the 15 students is 16 2⁄3 years, then the age of 40th student is

7/15 of 5/3 of a number is greater than 7/9 of 3/5 of the same number by 9. Find the quadruple of the number.

If the time increases by 7 years, then simple interest increases by Rs 8400 on a sum of Rs 6000. What is the rate (in percentage) of interest per annum?

If cosαcosβ=m and cosαsinβ=n,then the value of m2+n2 cos2β is

If the amount received at the end of 2nd and 3rd year at compound Interest on a certain Principal is Rs 9,600 and Rs 10,272 respectively, what is the rate of interest (in %)?

If the population of a town increases by 25% in the first year and increases by 36% in the second year, then what is the average rate (in percentage)of increase in the population?

A tower stands on the top of a building which is 40 metres high. The angle of depression of a point situated on the ground from the top and bottom of the tower are found to be 60 and 45 deg respectively. What is the height (in metres) of tower?

If (6x ­- 1) -­ (8x -­ 5) = 7, then the value of x is _______ .