Answer:
Arithmetic Sequence:
[tex]S=\frac{n}{2}(2a_{1}+(n-1)d)[/tex]
1. To determine difference (d):
d = 40-33 = 7
33-26 = 7
26-19 = 7
19-12 = 7
2. To determine number of terms (n):
d = 50 terms
Substitute,
[tex]S=\frac{n}{2}(2a_{1}+(n-1)d)[/tex]
[tex]S=\frac{50}{2}(2(12)+(50-1)7)[/tex]
[tex]S=9175[/tex] → Ans.
