$A$ certain amount earns simple interest of ₹ $1,750$ after $7$ years. Had the interest rate been $2 \%$ more per annum,how much more interest would it have earned (in ₹)?

If the simple interest on a certain sum of money is $\frac{4}{25}$ of the sum and the rate per cent equals the number of years,then the rate of interest (in $\%$) per annum is

David invested a certain amount in three different schemes $A, B$ and $C$ with the rate of interest $10 \% \text{ p.a.}, 12 \% \text{ p.a.}$ and $15 \% \text{ p.a.}$ respectively. If the total interest accrued in one year was ₹ $3200$ and the amount invested in scheme $C$ was $150 \%$ of the amount invested in scheme $A$ and $240 \%$ of the amount invested in scheme $B$, what was the amount (in ₹) invested in scheme $B$?

Sumit lent some money to Mohit at $5 \%$ $p.a.$ simple interest. Mohit lent the entire amount to Birju on the same day at $8 \frac{1}{2} \%$ $p.a.$ In this transaction,after a year Mohit earned a profit of ₹ $350.$ Find out the sum of money (in ₹) lent by Sumit to Mohit.

$A$ sum of $Rs. 1521$ is lent out in two parts in such a way that the simple interest on one part at $10 \%$ for $5 \,yr$ is equal to that of another part at $8 \%$ for $10 \,yr$. What will be the two parts of the sum?

In what time (in $years$) will ₹ $1200$ become ₹ $1344$ at $6 \%$ per annum simple interest?