Calculate the time in which $₹2500$ would become $₹2750$ at an interest rate of $8\%$ per annum.

In what time will money deposited in a bank will double itself if the rate of interest is $12\frac{1}{2}\%$ per annum.

What sum of money will amount to $₹7800$ at the rate of $6\%$ per annum, on simple interest in $5$ years$?$

At what rate per cent per annum will $₹6950$ 6950 produce $₹347.50$ 347.50 as simple interest in $5$ 5 months?

In what time will $₹1860$ amount to $₹2348.25$, if simple interest is calculated at $7\frac{1}{2}\%$ per annum.

At what rate per cent annum will $₹1640$ amount to $₹1968$ in $2\frac{1}{2}$ years.

At what rate per cent per annum will sum triple itself in $16$ years