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 $\%$).

Reena took a loan of ₹ $1,200$ with simple interest for as many years as the rate of interest. If she paid ₹ $432$ as interest at the end of the loan period,what was the rate of interest?

The principal (in ₹) that will yield ₹ $60$ as simple interest at $6 \%$ per annum in $5$ years is

In what time (in $years$) will a sum of money double itself at the rate of $20 \%$ per annum simple interest?

Mr. Mani invested an amount of ₹ $12000$ at a simple interest rate of $10 \%$ $p.a.$ and another amount at a simple interest rate of $20 \%$ $p.a.$. The total interest earned at the end of one year on the total amount invested was $14 \%$ $p.a.$. Find the total amount (in ₹) invested.

Nutan invests $Rs. 22400$ at a Simple Interest $(S.I.)$ rate of $12$ $p.c.p.a.$ How much amount will she receive after $7$ years (in $Rs.$)?