Evaluate the sum. $$\sum _ { k = 3 } ^ { 8 } 4 k$$
A) 264
B) 132
C) 8
D) 3
E) none of these

Question

Quizplus · Accepted Answer

We can use the formula for the sum of an arithmetic series, which is $\frac{(a_1 + a_n)n}{2}$ where $a_1$ is the first term, $a_n$ is the nth term, and $n$ is the number of terms. In this case, $a_1=4\cdot3=12$, $a_n=4\cdot8=32$, and $n=6$. Plugging these values into the formula gives us $\frac{(12+32)6}{2}=132$. Therefore, the answer is $\boxed{	extbf{(B)}}$.

Evaluate the Sum ∑k=384k\sum _ { k = 3 } ^ { 8 } 4 kk=3∑8​4k

Evaluate the Sum $\sum _ { k = 3 } ^ { 8 } 4 k$