Mohan borrowed an amount of Rs.18,000 and paid a simple interest of Rs.2,700 at 10% per annum. Find the duration for which he kept the borrowed amount. 

A music teacher borrowed ₹8,200 from a friend at 6.5% simple interest per annum. After 3 years, he repaid the amount along with a small donation of ₹280 to his friend's charity. Find the total amount he paid.

At what rate (in percentage) per year will a sum of money 5 times itself in 16 years on simple interest?

Amrita borrowed ₹ 6500 from a bank at 6% p.a. for 2 years and 6 months. The amount paid by her at the end of this period is

The simple interest on an amount for 6 years at 4% p.a. is ₹ 7,500 less than the simple interest on the same amount for 11 years. Find the amount.

A sum was put at simple interest at a certain rate for 2 years. Had it been put at 3% higher rate, it would have fetched ₹ 300 more. Find the sum.

What is the rate percent and time needed, both of them being equal in value, for the simple interest on a certain sum to be 36 over 100 of that sum?

Ravi lent ₹12,000 to his friend at a simple interest rate of 8% per annum. After how many years will the total amount become ₹16,800 ?

What sum (in ₹) will earn a simple interest of ₹840 in 3 years at 20% per year rate of interest?

Simple interest of ₹375 is obtained on a sum of money for a period of 3 years at a rate of 2% per annum. Find the sum (in ₹).

A sum amounts to ₹ 9075 in $$1\frac{1}{3}$$​ years at 15% p.a, interest compounded 8-monthly. What is the simple interest (in ₹) on the same sum for the same period and at the same rate of interest ?