An amount fetched a total simple interest of ₹ $3200$ at the rate of $6.25 \%$ per year in $4$ years. What is the amount (principal) in ₹?

Dalajit lent ₹ $10800$ to Jaabir for $3$ $years$ and ₹ $7500$ to Kabir for $2$ $years$ on simple interest and received ₹ $1422$ in all from both of them as interest. The rate of interest (in $\%$) per annum is

An automobile financier claims to be lending money at simple interest,but he includes the interest every six months for calculating the principal. If he is charging an interest of $10 \%$ per annum,the effective rate of interest (in $\%$) becomes:

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 $\%$):

Arun gives his wife Asha a birthday gift,giving her each year a number of rupees equal to the number of years of her age. If her birthday falls on $August \, 8$,what sum must be placed at simple interest at $7 \%$ on $January \, 1$,before she is $42$,in order to raise the required sum (in $Rs.$)?

If the simple interest on a certain sum of money for $2$ $years$ is one-fifth of the sum,then the rate of interest (in $\%$) per annum is