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 $\%$).

$A$ sum of $Rs. 1521$ is lent out in two parts in such a way that the simple interest on one part at $10 \%$ for $5 \,yr$ is equal to that of another part at $8 \%$ for $10 \,yr$. What will be the two parts of the sum?

If the simple interest of ₹ $1$ for $1$ month is $1$ paisa,then the rate per cent per annum will be:

Gaurav borrowed $Rs. 800$ at $6 \%$ and Naresh borrowed $Rs. 600$ at $10 \%$. After how much time will they both have equal debts?

In what time (in $years$) will ₹ $1200$ become ₹ $1344$ at $6 \%$ per annum simple interest?

Adam borrowed some money at the rate of $6 \% \text{ p.a.}$ for the first two years,at the rate of $9 \% \text{ p.a.}$ for the next three years,and at the rate of $14 \% \text{ p.a.}$ for the period beyond five years. If he pays a total interest of ₹ $11,400$ at the end of nine years,how much money (in ₹) did he borrow?