A sum of money placed at compound interest triples itself in 9 year. In how many years will if amount to 243 times itself?

A sum of Rs. 2000 amounts to Rs. 4000 in two years at compound interest. In how many years does the same amount becomes Rs. 8000. 

On a certain principal if the simple interest for two years is Rs. 1400 and compound interest for the two years is Rs. 1449, what is the rate of interest? 

What will be compound interest on a sum of Rs. 1000 at the rate of interest 10% after 5 years?

What is compound interest accrued on an amount of Rs 45000 in 2 yr @ 9% per annum ? 

Raman took a loan of Rs. 15000 from Laxman. He was agreed that for the first three years rate of interest charged would be at 8% Simple Interest per annum and at 10% Compound Interest (compounded, annually) from the fourth year onwards. Ram did not pay anything until the end of the fifth year. How much would he repay if he clears the entire amount, only at the end of fifth year? (inRs.)

If the amount received at the end of 2nd and 3rd year as Compound Interest on a certain Principal is Rs 24200, and Rs 26620 respectively, what is the rate (in %) of interest?