$A$ sum of money invested at compound interest amounts to ₹ $800$ in $3$ years and to ₹ $840$ in $4$ years. The rate of interest (in $\%$) per annum is

How many statements are required to find the rate of interest percent $p.a.$?
$Statements:$
$I$. The difference between the compound interest and simple interest earned in two years on the amount invested is ₹ $100$.
$II$. The amount becomes ₹ $19,500$ in three years on simple interest.
$III$. The simple interest accrued in two years on the same amount at the same rate of interest is ₹ $3,000$.

$A$ sum of ₹ $1260$ is borrowed from a money lender at $10 \%$ p.a. compounded annually. If the amount is to be paid back in two equal annual instalments,find out the annual instalment (in ₹).

What would be the $C.I.$ obtained on an amount of $Rs. 4800$ at the rate of $5$ $p.c.p.a$ for $3$ years (in $Rs.$)?

If the difference between the simple interest and compound interest earned on an amount at $15$ $p.c.p.a.$ at the end of $3$ years is $Rs. 595.35$,what is the amount (in $Rs.$)?

What will be $C.I.$ (in $Rs.$) on an amount of $Rs. 10000$ at the rate of $20$ $p.c.p.a.$ in two years if the interest rate is compounded half-yearly?