The simple interest on a certain sum at $4 \%$ per annum for $2$ years is ₹ $80$. The compound interest (In ₹) on the same sum for the same period is

If a sum of money placed at compound interest, compounded annually, doubles itself in $5$ years, then the same amount of money will be $8$ times of itself in (In $years$)

Find the least number of complete years in which a sum of $Rs. 1500$ at $25 \%$ compound interest will be more than double.

The compound interest on $\$ 1,800$ at $10 \%$ per annum for a certain period of time is $\$ 378 .$ Find the time in years.

What would be the $C.I.$ on $Rs. 17500$ at the rate of $12$ $p.c.p.a.$ after $2$ years (In $Rs.$) ?

The difference between compound interest and simple interest on a sum for $2$ years at $10 \%$ per annum, when the interest is compounded annually, is ₹ $20$. If the interest were compounded half yearly, the difference in two interests (In ₹) will be