Rs. 1000 is deposited at 10 per cent simple interest. Check if the interest amount at the end of every year is in A.P. If this is A.P. then find amount of the interest after 20 years. For this complete the following activity.

Answer

Amount of simple interest after 20 years is Rs. 2000.

Explanation

Simple interest`=(PxxRxxN)/(100)`
Simple interest after 1 year `=(100xx10xx1)/(100)=100`
Simple interest after 2 year `=(1000xx10xx2)/(100)=200`
Simple interest after 3 years `(1000xx10xx3)/(100)=300`
According to this, the simple interest for 4, 5, 6. years will be 400, 500, 600 respectively From this `d = 100 and a = 100` Amount of simple interest after 20 years.
`t_(n)=a+(n-1)d`
`t_(20)=100+(20-1)100 [100+19xx100=100+1900]`
`t_(20)=2000`