If a sum of money doubles itself in $8$ years at $S.I.$,then the rate of interest per annum (in $\%$) is: (in $.5$)

$A$ sum of money amounts to ₹ $9,800$ after $5$ $years$ and ₹ $12,005$ after $8$ $years$ at the same rate of simple interest. The rate of interest (in $\%$) per annum is

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

$A$ sum of money will double itself in $16$ years at simple interest at an yearly rate of (in $\%$):

The difference between the interest received from two different banks on $₹ 5,000$ for $2$ $years$ is $₹ 25$. The difference between their rates is (in $\%$):

$₹ 800$ 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?