The population of Mumbai increases by $5 \%$ per annum. Its population was $100000$ in $2004$. What was its population after $3$ years?

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

Prabhat took a certain amount as a loan from a bank at the rate of $8 \%$ simple interest per annum and gave the same amount to Ashish as a loan at the rate of $12 \%$ per annum on simple interest. If at the end of $12$ years,he made a profit of $Rs. 320$ in the deal,what was the original amount (in $Rs.$)?

$A$ sum of money lent out at simple interest amounts to ₹ $720$ after $2$ $years$ and to ₹ $1,020$ after a further period of $5$ $years$. The sum is (In ₹)

$A$ certain sum becomes $5$ times in $3$ years at simple interest. In how many years will it become $13$ times?

Nutan invests $Rs. 22400$ at a Simple Interest $(S.I.)$ rate of $12$ $p.c.p.a.$ How much amount will she receive after $7$ years (in $Rs.$)?