If the difference between CI and SI for 3 years at the rate of 10% is Rs 31. Find the principle.

If the difference of interest of two banks of Rs 500 is Rs 2.50, find the difference between their rates.

A person invests money in three different schemes for 6 years, 10 years and 12 years at 10%, 12% and 15% simple interest respectively. At the completion of each scheme, he gets the same interest. The ratio of his investments is-

2 years, a sum was put at SI at a certain rate. If the rate was 3 % higher, it would have fetched 300 more. What will be the sum? 

The amount of Rs 400 becomes Rs 480 in 4 years. If the rate of interest is increased by 2 percent, how much will it be?

What annual instalment will discharge a debt of ₹ 6450 due in 4 years at 5% simple interest?

A certain sum of money lent out at simple interest amounts to Rs. 2400 in 4 years and Rs. 3000 in 6 years. Find the rate of interest per annum?

An amount doubles itself in 5 years simple interest. What is the rate of interest per year?