Quantitative Aptitude - Arithmetic Ability Questions

The lengths of diagonals of a rhombus are 24cm and 10cm the perimeter of the rhombus (in cm ) is :

If 15 persons can do a job in 30 days, then 30 persons with twice the efficiency can do the same job in how many days?

The mean of 10 observations is 17. One more observation is included and the new mean becomes 16. The 11th observation is

The sum of the ages of Rohit and Ankit is 78. Rohit's age is twice the age of Ankit. What is the age (in years) of Rohit?

A right circular cylinder is partially filled with water. Two iron spherical balls are completely immersed in the water so that the height of the water in the cylinder rises by 4 cm. If the radius of one ball is half of the other and the diameter of the cylinder is 18 cm, then the radii of the spherical balls are

A cricketer, whose bowling average was 12.4 runs/wicket takes 5 wickets for 22 runs in a match, thereby decreases his average by 0.4. The number of wickets, taken by him before this match was:

If x = a cosθ+ b sinθ and y = b cosθ- a sinθ, then x2 + y2 is equal to

Find the sum of interior angles of a dodecagon?