How much time it will take for an amount of Rs.4000 to yield RS.450 as interest at 5% per annum of simple interest?

To calculate the time it will take for an amount of Rs.4000 to yield Rs.450 as interest at 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.450), the Principal (P = Rs.4000), and the Rate (R = 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 = 450 * 100 / (4000 * 5)

Calculating the above expression gives you:

T = 2.25 years

So, it will take 2.25 years for an amount of Rs.4000 to yield Rs.450 as interest at 5% per annum of simple interest.