1.What is the minimum number of full years required for an investment to more than double at a compound interest rate of 20% per annum?
2.If a principal amount invested at compound interest doubles in 5 years, how long will it take to become eight times the original amount at the same interest rate?
3.An amount invested at compound interest grows to Rs. 800 after 3 years and to Rs. 840 after 4 years. What is the annual interest rate?
4.What is the effective annual interest rate equivalent to a nominal rate of 6% per year compounded semi-annually?
5.A certain principal amount yields Rs. 660 as simple interest over 2 years, while the compound interest for the same period is Rs. 696.30. If the interest rate remains constant in both cases, what is the rate of interest?
6.What is the principal amount (in Rs.) if the difference between the simple interest and compound interest (compounded annually) on it for 2 years at a rate of 4% per annum is Rs. 1?
7.An amount increases by 60% in 6 years under simple interest. What will be the compound interest on Rs. 12,000 after 3 years at the same interest rate?
8.The simple interest on a certain principal for 3 years at an annual rate of 8% is equal to half the compound interest earned on Rs. 4000 over 2 years at 10% per annum. What is the principal amount invested at simple interest?
9.If the compound interest on a principal amount for 2 years at an annual rate of 10% is Rs. 525, what is the simple interest on the same principal for 4 years at an annual rate of 5%?
10.The compound interest on a principal amount for 2 years at an annual rate of 12.5% is Rs. 510. What is the simple interest on the same principal at the same rate and for the same duration?
11.What is the original principal amount that grows to Rs. 4913 in 3 years at an annual compound interest rate of 6.25%?
12.If Rs. 30,000 is invested at an annual compound interest rate of 7%, and the interest earned is Rs. 4,347, what is the duration of the investment in years?
13.What is the difference between the compound interest and simple interest on Rs. 1200 for one year at an annual rate of 10%, when interest is compounded semi-annually?
14.What is the difference between the compound interest and simple interest on Rs. 1000 at an annual rate of 10% over 4 years?
15.A principal amount earns Rs. 50 as simple interest over 2 years at an annual rate of 5%. What will be the compound interest on the same principal, at the same rate and time period?
16.Calculate the compound interest on Rs. 15,625 for a period of 9 months at an annual interest rate of 16%, compounded quarterly.
17.What is the difference in compound interest on Rs. 5000 for 1.5 years at an annual rate of 4% when compounded annually versus semi-annually?
18.If a principal amount doubles in value after 4 years at compound interest, how many years will it take for the amount to become eight times the original?
19.If a principal amount triples in 3 years under compound interest, after how many years will it become nine times the original amount?
20.If the compound interest on a certain principal amount for 2 years is Rs. 41 and the simple interest for the same period is Rs. 40, what is the annual interest rate?