$A$ money lender lends ₹ $400$ for $3$ $years$ to a person and ₹ $500$ for $4$ $years$ to another person at the same rate of simple interest. If altogether he receives ₹ $160$ as interest,what is the rate of interest per annum (in $\%$)?

What is the simple interest (in ₹) on ₹ $5400$ in $5$ years at the rate of $12 \%$ per annum?

Mr. Gupta deposits ₹ $3000$ in a bank at $10 \%$ $p.a.$ and ₹ $5000$ in another bank at $8 \%$ $p.a.$. The rate of interest (in $\%$) for the whole sum is

$A$ sum of ₹ $16800$ is divided into two parts. One part is lent at a simple interest rate of $6 \%$ per annum and the other at $8 \%$ per annum. After $2$ years,the total amount received is ₹ $19000$. The sum lent at the rate of $6 \%$ simple interest (in ₹) is:

The simple interest on a sum is $\frac{1}{16}$ of the principal and the number of years is equal to the rate per cent per annum. The rate per cent per annum is (in $.5$)

$A$ sum was doubled with $12 \frac{1}{2} \%$ rate of simple interest per annum. The time taken (in years) for that sum is: