Quantitative Aptitude - Arithmetic Ability Questions

A person lent certain sum of money at 10% per annum simple interest. In 20 years the interest amounted to Rs 500 more than the sum lent. What was the sum lent (in Rs)?

If 1/2 is added to a number and the sum is multipled by 3, the result is 21. Then the number is

Marked price of an item is Rs 200. On purchase of 1 item discount is 5%, on purchase of 2 items discount is 14%. Rajeshri buys 3 items, what is the effective discount? 

ABCDEF is a regular hexagon of side 12 cm. What is the area (in cm2) of the triangle ECD?

If a - b = -5 and a2+b2=73, then find ab.

When a number is increased by 24, it becomes 110% of itself. What is the number?

In the given figure, a circle touches the sides of the quadrilateral PQRS. The radius of the circle is 9 cm. RSP = SRQ = 60 deg and PQR = QPS = 120 deg. What is the perimeter (in cm) of the quadrilateral?