Chapter 11 - Cumulative Review - Page 670: 49

$S_{30}=465$

The first 30 positive integers is an arithmetic sequence with $a_1=1$ and $a_n=30$. Using $S_n=\dfrac{n}{2}(a_1+a_n)$, then, \begin{array}{l} S_{30}=\dfrac{30}{2}(1+30) \\ S_{30}=15(31) \\ S_{30}=465 .\end{array}