$A$ certain sum of money amounts to ₹ $2200$ at $5 \%$ $p.a.$ rate of interest,and ₹ $2320$ at $8 \%$ interest in the same period of time. The period of time (in years) is:

If ₹ $500$ amounts to ₹ $725$ at $9 \%$ simple interest in some time,what will ₹ $600$ amount (in ₹) to at $11 \%$ in the same time?

$A$ sum of money will double itself in $16$ years at simple interest at an yearly rate of (in $\%$):

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

$A$ sum of $Rs. 725$ is lent in the beginning of a year at a certain rate of interest. After $8$ months,a sum of $Rs. 362.50$ more is lent but at the rate twice the former. At the end of the year,$Rs. 33.50$ is earned as interest from both the loans. What was the original rate (in $\%$) of interest?