$A$ sum of $Rs. 1500$ amounts to $Rs. 3000$ in five years at a certain rate of simple interest. If the rate of interest is increased by $1 \%$,the same sum in the same time would amount (in $Rs.$) to:

Arun invested a sum of money at a certain rate of simple interest for a period of $4$ years. Had he invested the same sum for a period of $6$ years,the total interest earned by him would have been $50\%$ more than the earlier interest amount. What was the rate of interest per cent per annum?

$A$ sum of money becomes $Rs. 1100$ in $2$ years and $Rs. 1400$ in $6$ years at $S.I.$ Find the rate percent.

$A$ sum of money put at simple interest trebles itself in $15$ years. The rate per cent per annum is (in $\%$):

If a sum of money at simple interest doubles itself in $6$ years,it will become four times in how many years?

The rate of interest on a sum is $4 \%$ per annum for the first $2$ years,$6 \%$ per annum for the next $4$ years,and $8 \%$ per annum for the period beyond $6$ years. If the simple interest accrued by the sum for a total period of $9$ years is ₹ $1120$,find the sum. (In ₹)