find the sum of the first 25 trrms of the series 5.6+6.7+7.8+.....
find the sum of the first 25 trrms of the series 5.6+6.7+7.8+.....
we have ,
5.6 + 6.7 + 7.8 + 8.9 +…………upto 25 terms
We have first term (a) = 5.6
common Difference = 6.7 – 5.6 = 1.1
= 7.8 – 6.7 = 1.1
= 8.9 – 8.9 = 1.1
This series is in arithmetic progression ,
So ,we have the formula for sum
sum =
on putting the values , we get
=
=
=
=
= 25*18.8
= 470 ans