Find the sum of the first n terms of the sequence.
-$25,31,37,43 , \ldots ; n = 10$
A) 395
B) 520
C) 550
D) 605

Question

Quizplus · Accepted Answer

The given sequence is an arithmetic sequence with the first term $a = 25$ and common difference $d = 31 - 25 = 6$. The sum of the first $n$ terms of an arithmetic sequence is given by $S_n = \frac{n}{2}[2a + (n-1)d]$. Substituting $n = 10$, $a = 25$, and $d = 6$, we get $S_{10} = \frac{10}{2}[2(25) + (10-1)6] = 5[50 + 54] = 5 \times 104 = 520$.

Find the Sum of the First N Terms of the Sequence