Question

Question 5.5. Find the sum of the first 27 terms: 2.5 + 5.5 + 8.5 + 11.5 + …
(Points : 1)
13.5

83

756

1120.5

Answer 1

@BillBell

Answer 2

\[\frac{ n }{ 2 }(2a+(n-1)d)\]
where n= no. of terms , d= common difference and a = first term

Answer 3

after solving
we get last option