Girish invested some money in a bank. After $8$ years,his amount became triple. How many times of the original sum will the money become in $20$ years at simple interest?

What amount (in $Rs.$) would a man have received on a principal of $Rs. 4000$ after $2$ years at a simple interest rate of $5$ $p.c.p.a.$?

$A$ lends ₹ $2500$ to $B$ and a certain sum to $C$ at the same time at $7 \%$ $p.a.$ simple interest. If after $4$ $years,$ $A$ altogether receives ₹ $1120$ as interest from $B$ and $C,$ then the sum lent (in ₹) to $C$ is

The simple interest on a sum of money will be ₹ $600$ after $10$ $years$. If the principal is trebled after $5$ $years$,then what will be the total interest (in ₹) at the end of the tenth year?

Mrs. Sushma lent out an amount of $Rs. 3000$ at $4 \%$ p.a. and some other amount at $5 \%$ p.a. If at the end of the year she received $Rs. 138$ as total interest,what amount (in $Rs.$) did she lend out at $5 \%$ p.a.?

$A$ sum of money put at simple interest trebles itself in $15$ years. The rate per cent per annum is (in $\%$):