On a sum of money,the simple interest for $2$ years is ₹ $660$,while the compound interest is ₹ $696.30$,the rate of interest being the same in both the cases. The rate of interest (in $\%$) is

$A$ person takes a loan of ₹ $10,000$ at an interest rate of $10 \%$ compounded annually for a period of $4$ years. How much interest (in ₹) does he have to pay?

Suneeta borrowed a certain sum from Reena for $2 \,yr$ at simple interest. Suneeta lent this sum to Venu at the same rate for $2 \,yr$ at compound interest. At the end of $2 \,yr$,she received $Rs. 110$ as compound interest but paid $Rs. 100$ as simple interest. Find the sum and the rate of interest.

The compound interest earned by Shivam on a certain amount at the end of $2$ years at the rate of $8 \, p.c.p.a.$ was $Rs. 1414.4$. What was the total amount that Shivam got back at the end of $2$ years in the form of principal plus interest earned (in $Rs.$) (in $.4$)?

$A$ bank offers $5 \%$ compound interest calculated on a half-yearly basis. $A$ customer deposits $Rs. 1600$ each on $1^{st}$ January and $1^{st}$ July of a year. At the end of the year,the amount (in $Rs.$) he would have gained by way of interest is:

The difference between the compound and simple interest on a sum of money for $2$ years at $6 \frac{1}{4} \%$ per annum is $Rs. 10$. The sum (in $Rs.$) is