Rashmi lent $Rs. 600$ to Geeta for $2 \,yr$ and $Rs. 150$ to Seeta for $4 \,yr$ at the same rate of interest and received altogether $Rs. 80$ as simple interest from both. Find the rate of interest (in $\%$).

Sumit lends ₹ $10000$ for $2$ $years$ at $20 \%$ per annum simple interest. After $1$ $year,$ he receives ₹ $6000$. How much (in ₹) will he receive next year?

At what rate per cent of simple interest will a sum of money double itself in $12$ years?

If the simple interest on a certain sum of money after $6 \frac{1}{4}$ years is $\frac{3}{8}$ of the principal,then the rate of interest (in $\%$) per annum is

Ram deposited a certain sum of money in a company at $12 \%$ per annum simple interest for $4$ years and deposited an equal amount in a fixed deposit in a bank for $5$ years at $15 \%$ per annum simple interest. If the difference in the interest from the two sources is $Rs. 1350$,then the sum (in $Rs.$) deposited in each case is:

What time (in years) is taken by a sum of $Rs. 7000$ to become $Rs. 10500$ at the rate of $5 \%$ per annum simple interest?