This is an arithmetic series, where S5 means the sum of the first 5 numbers in the series. The general formula is:
Sn = (n/2)(a1 + an)
So,
a1 = 1 + 5/2(1) = 3.5
a5 = 1 + 5/2(5) = 1.5
S5 = (5/2)(3.5+1.5)
S5 = 12.5
<em>The answer should be 12.5</em>
I’m almost positive it’s #1 my bad if it isn’t
Two positives multiplied together give us a positive answer. and 18 • 6 is 108.
108 is the answer
hope this helped, xx
