How much time will it take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest?

To calculate the time it will take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest, you can use the formula for simple interest:

I = PRT/100

where: I = Interest P = Principal amount (the initial amount of money) R = Rate of interest T = Time in years

In this case, you know the Interest (I = Rs. 81), the Principal (P = Rs. 450), and the Rate (R = 4.5%). You want to find the Time (T).

Rearranging the formula to solve for T gives you:

T = I * 100 / (P * R)

Substituting the given values into the formula gives you:

T = 81 * 100 / (450 * 4.5)

Calculate the above expression to find the value of T. This will give you the time in years it will take for Rs. 450 to yield Rs. 81 as interest at 4.5% per annum.