Quantitative Aptitude - Arithmetic Ability Questions

What is the curved surface area (in cm²) of a hemisphere of diameter 42 cm?

The simple interest on a sum for 5 years is two­fifth of the sum. The rate of interest per annum is

The difference between the greatest and least five­ digit numbers formed by the digits 2,5,0,6,8 is (repetition of digits are not allowed)

In ΔABC measure of angle B is 90 deg. If tanA = 15/8, and AB = 0.8 cm, then what is the length (in cm) of side AC?

If X = 423 + 32 then find the value of  ( X + 1X ).

The ratio of total surface area and volume of a sphere is 1 : 7. This sphere is melted to form small spheres of equal size. The radius of each small sphere is 1/6th the radius of the large sphere. What is the sum (in cm2) of curved surface areas of all small spheres?

The difference between the ages of mother and son was 21 when mother's age was 43. If father is elder by 3 years to mother, what will be the difference between the ages of son and father when father attains 50 years?

15 small rods, each of length 23 2/7 m are joined to make a big rod. What then is the length of the big rod?