Question

On a certain sum the interest paid after 3years is ₹450 at 5% rate of interest per annum find the sum

Answer 1

Let the principle or the sum be P.
Rate=5%,Time=3 years and interest=Rs450.
We know,
S.I=PRT/100
Therefore,Rs450=(P*5*3)/100.
or,Rs450=3P/20
or,P=(Rs450*20)/3
or,P=Rs9000/3
P=3000.

Answer 2

Given:

On a certain sum, the interest paid after 3years is ₹450 at a 5% rate of interest per annum

To Find:

Find the sum

Solution:

To find a sum that is been invested for a certain amount of time over a rate of interest can be expressed by the following formula,( this formula gives the interest after a certain amount of time and not the final amount, to get the amount we will need to add the initial amount in this interest to get the final amount)

$I=\frac{PRT}{100}$

where,

          P= principal amount

          R= rate of interest

          T= time period

Now applying the values in the question to get the value of the P which is the principal sum, it goes as,

$450=\frac{P*5*3}{100}\\P=3000$

so the amount Rs 3000, when invested at 5% pa for 3 years, will get you 450 as interest

Hence, the sum is Rs3000.