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

The sum of money that will produce ₹ $1770$ interest in $7 \frac{1}{2}$ years at $8 \%$ simple interest per annum is:

Two equal amounts are deposited in two banks,each at $15 \%$ per annum,for $3 \frac{1}{2}$ years and $5$ years respectively. If the difference between their interests is ₹ $1440$,each sum is (In ₹):

The rate percent per annum at which ₹ $1200$ amounts to ₹ $1440$ in $4$ years is:

What sum lent at $10 \%$ per year on $S.I.$ will amount to $Rs. 450$ in $2$ years?

$A$ lent ₹ $6000$ to $B$ for $2$ $years$ and ₹ $1500$ to $C$ for $4$ $years$ and received altogether from both ₹ $900$ as simple interest. The rate of interest is (in $\%$):