If $${8+2\sqrt{3} \over 3\sqrt{3}+5}=a\sqrt{3}-b$$, then the value of a+b is equal to:

A certain sum amounts to ₹15,500 in 2 years at 12% p.a. simple interest. The same sum will amount to what in$$1{1\over 2}$$ years at 10% p.a., if the interest is compounded half yearly (nearest to ₹1)?

A sum triple itself in 9 years at simple interest. Find the rate of interest per annum is.

What is the ratio of the simple interest earned on a certain amount at the rate of 21% per annum for 8 years to that earned on the same sum at the same rate for 21 years?  

In 5 years, the simple interest on an amount of Rs. X is $$2\over 5$$ of the principal. The rate of interest per annum is:

The difference of simple interest from two banks on ₹8,000 in 3 years is ₹800. If the rate of interest per annum in two banks are R1 and R2, then what is the value of R1 - R2? (Where R1 > R2)

A sum of money doubles itself in 7 years at simple interest. In how much time will it become 5 times of itself?

A person deposited ₹15,600 in a fixed deposit at 10% per annum simple interest. After every second year he adds his interest earned to the principal. The interest at the end of 4 years is: