Question

find the sum of the following 5,10,15 .... upto 25 terms​

Answer 1

Answer:

let let 'a' and 'd' the first term and the common difference respectively

a =5 d=5 n=25

Sn=n/2(2a+(n-1)d)

Sn=25/2(2*5+(25-1)5)

Sn=25/2(10+120)

Sn=25/2*130

Sn=25×65

Sn=1625

i hope my answer is right

Answer 2

hope it will hopefull for you