How many years will it take for an amount of $Rs. 600$ to yield $Rs. 120$ as interest at $10 \%$ per annum of $S.I.$?

Brinda borrowed ₹ $1000$ to build a hut. She pays $5 \%$ simple interest. She lets the hut to Ramu and receives a rent of ₹ $12 \frac{1}{2}$ per month from Ramu. In how many years would Brinda clear off the debt?

Two equal sums were lent at simple interest for $4$ years and for $3$ years respectively. The rate of interest in the latter case was $3 \%$ higher than that of the former case,but the amount in each was $Rs. 1088$. Find the rate of interest (in $\%$) of the former case?

$₹ 800$ becomes $₹ 956$ in $3$ years at a certain rate of simple interest. If the rate of interest is increased by $4 \%$,what amount (in $₹$) will $₹ 800$ become in $3$ years?

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?

$A$ person receives a simple interest of ₹ $1,000$ on a certain principal at the rate of $5 \%$ $p.a.$ in $4$ years. What compound interest (in ₹) will that person receive on twice the principal in $2$ years at the same rate?