Quantitative Aptitude - Arithmetic Ability Questions

Two adjacent sides of a parallelogram are 21 cms and 20 cms. The diagonal joining the end points of these two sides is 29 cms. The area of the parallelogram (in sq.cms) is

15 years ago, Shyam was twice as old as Prbhat. Five years from now Prabhat's age will be 5/8 of Shyam's age. What is Shyam's current age?

A natural number, when divided by 4, 5, 6 or 7, leaves a remainder of 3 in each case. What is the smallest of all such numbers?

Pipes A, B and C are attached to an empty cistern. While the first two can fill the cistern in 4 and 10 hrs, respectively, the third can drain the cistern, when filled, in 6 hrs. If all the three pipes are opened simultaneously when the cistern is half-full, how many hours will be needed to fill the cistern?

If 2sec2x - tan2x = 5 and 0° ≤ x ≤ 90°, then x = ?

Square root of 0.9 is equal to

Find the average of all prime numbers from 1 to 50.

The simple interest on a sum is 7/8 of the principal for 5 years. What is the rate (in percentage) of interest per annum?