Answer:
330
Step-by-step explanation:
Evaluate the sum of 14 terms and subtract the sum of the first 3 terms
The sum to n terms of an arithmetic sequence is
[tex]S_{n}[/tex] = [tex]\frac{n}{2}[/tex] [ 2a₁ + (n - 1)d ], so
[tex]S_{14}[/tex] = 7 [ (2 × 6) + (13 × 3)]
= 7(12 + 39) = 7 × 51 = 357
[tex]S_{3}[/tex] = 6 + 9 + 12 = 27
Sum of terms from 4 th to 14 th = 357 - 27 = 330
