The simple interest on a sum of money will be ₹ $600$ after $10$ $years$. If the principal is trebled after $5$ $years$,then what will be the total interest (in ₹) at the end of the tenth year?

At what rate per cent per annum will a sum of money double in $16$ years (in $.25$)?

$A$ sum of ₹ $1,550$ is lent out in two parts,one at $8 \%$ and another at $6 \%$. If the total annual income is ₹ $106$,find the money lent at each rate.

$A$ part of $Rs. 38800$ is lent out at $72 \%$ per annum for six months. The rest of the amount is lent out at $5 \%$ per annum after one year. The ratio of interest after $3$ years from the time when the first amount was lent out is $5: 4$. Find the second part that was lent out at $5 \%$ (in $Rs.$).

$A$ man invested $\frac{1}{3}$ of his capital at $7 \%$,$\frac{1}{4}$ at $8 \%$,and the remaining at $10 \%$ rate of simple interest. If his annual income from interests is ₹ $561$,then the total capital invested (in ₹) was:

If the simple interest on ₹ $x$ at a rate of $a \%$ for $m$ years is same as that on ₹ $y$ at a rate of $a^2 \%$ for $m^2$ years,then $x: y$ is equal to