## Precalculus (6th Edition) Blitzer

$440$
We need to use the formula $S_n=\dfrac{n(a_1+a_2)}{2}$ Here, $a_1=5$ and $n=16$ Now, $S_n=\dfrac{n(a_1+a_2)}{2}$ and $S_{16}=\dfrac{16(5+50)}{2}=440$