Given the first and last term, a = 6, t9 = 24, how do you find the sum of the arithmetic series?

Question

8493 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-02-03T18:03:24

Formula is #S_n = n(2a+(n-1)d)/2#
#t_n=a+(n-1)d#
So #S_n = n(a+l)/2#
So sum is 9(6+24)/2=135