What is the sum of the first five terms of the series 35 30 25

By keenly investigating the given sequence, it is evident that is an arithmetic sequence with a common difference (d) of - 5. To solve for the sum (S) (also called arithmetic series),

Sn = (n/2) x (2a1 + (n - 1) x d)

where n is 5 and a1 is 35. Substituting the given known values,

S5 = (5/2) x (2 x 35 + (5 - 1) x - 5) = 125

Thus, the sum of the first five terms is 125.