What sum of money will amount to Rs. 520 in 5 years and to Rs 568 in 7 years on simple interest?

For a certain period, simple interest on Rs. 1000 at 10% per annum is Rs. 100 more than that on Rs. 800. Find the period (in years).

The interest earned on $\rupee 25000$ in 5 years at simple interest is $\rupee 1500$. What is the rate of interest?

Simple interest on a certain sum of money for 3 years at 8% per annum is half of the compound interest on ₹ 6000 for 2 years at 10% per annum. Find the sum on which simple interest is calculated ?

The simple interest of an amount is $\frac{16}{25}$ of the principal. Find the rate % PA, if the time and rate both are numerically equal.

In how many years will a sum of money double itself at 12.5% p.a., at simple interest?

In what time will the simple interest on ₹2200 at 6% per annum be the same as that on ₹1650 at 9% per annum in 10 years?