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

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

What sum of money (in $Rs.$) at compound interest will amount to $Rs. 5305.53$ in $3$ years,if the rate of interest is $1 \%$ for the first year,$2 \%$ for the second year,and $3 \%$ for the third year?

What will be the amount (in ₹) if a sum of ₹ $5000$ is placed at compound interest for $3$ years,while the rate of interest for the first,second,and third years is $2\%$,$3\%$,and $4\%$ per annum,respectively?

If a sum of money at compound interest amounts to thrice itself in $3$ years,then in how many years will it be $9$ times itself?

$A$ certain sum of money (in $Rs.$) gives $Rs. 500$ as Simple Interest $(S.I.)$ at $5 \%$ per annum for $1$ year. What is the Compound Interest $(C.I.)$ on the same sum at the same rate at the end of $2$ years?