A certain sum doubles in 7 years at simple interest. The same sum under the same interest rate will become 4 times in how many years.:

A principal increase by 50 percent in five years at the rate of simple interest. What will be the compound interest for 3 years at Rs 20,000 with the same interest rate?

A rational number between $${3\over4} $$ and $${3\over8} $$ is :

The ratio between three number is 2 : 3 : 5 and the sum of these number is 275. Find the smallest number.

What is the difference between compound interest and simple interest on Rs. 2500 for 2 years at 4% per annum?

Five years ago the sum of the ages of A and B was 58 years. The difference between B's age 8 years ago and A's age 8 years hence is 16 years. The ratio of the present ages of A and B is:

If (a+b)=16 and a³+b³=1456, then what is the value of ab?

By selling a bicycle for Rs. 2,850 a shopkeeper gain 14%. If the profit is reduced to 8 %, then the selling price will be