Question

A sum of Rs.1000 is invested at 8% simple interest per annum. Calculate the interest at the end of 1, 2, 3, ……. Years. If the sequences of interests an AP? Find the interest at the end of 30 years.

Answer 1

Principal=p=Rs1000
Rate of interest =r=8%
Time =t=1yr
Simple interest=I
I=ptr/100
=(1000*8*1)/100
=Rs80
2) interest for 2 yrs =2I=2*80=160
3) interest for 3yrs=3*I=3*80=240
4)interest for 4yr =4*I=4*80=320
Interests 80,160,240,320....are in ap
First term = a=80
Common difference=d=a2-a1=160-80=80
nth term =an =a+(n-1)d

Here n=30
a30=80+(30-1)80
=80+29*80
=30*80
=Rs2400

Answer 2

plz refer to this attachment