What capital will a person earn a monthly interest of $₹20$ at $6$ paise per rupee per year simple interest?

The simple interest on a sum of money for $3$ years is $₹960$ and for another period at the same rate of interest is $₹1,600$. How long is the second period in years?

Jamna Das borrowed $₹12,650$ from the Mukhia of the village at $18\%$ per annum. After $3$ years, he paid $₹10,381$ and gave a buffalo to clear the debt. What is the cost of the buffalo?

A certain sum of money amounts to $₹2,200$ in $1$ year at simple interest, at a certain rate and to $₹2,800$ at the same rate in $4$ years. Find the sum and rate percent. 

A sum of money invested at $18\%$ per annum amounts to $₹7,425$ in $2$ years and one month. What will it amount to in $2$ years and $6$ months at $16\%$ per annum?

If $₹360$ amounts to $₹532.80$ in $3$ years, what will $₹720$ amounts to in $5\frac{1}{2}\mathrm{years}$ at the same rate percent per annum?

A man lent $₹2,000$ part of this at $6\%$ and the rest at $4\%$ per annum, the whole annual interest amounted to $₹90$. How much did he lend at $6\%$?

The simple interest on a certain sum for $5$ years at $14\%$ per annum is $₹50$ more than the simple interest on the sum for $4$ years at $15\%$ per annum. Find the sum.

Divide $₹6000$ into two parts so that the simple interest on the first part for $2$ years at $6\%$ per annum may be equal to the simple interest on the second part for $3$ years at $8\%$ per annum.