Answer
$a_6 = 33$
Work Step by Step
RECALL:
The $n^{th}$ term, $a_n$, of an arithmetic sequence can be found using the formula:
$a_n=a_1 + d(n-1)$
where
$a_1$ = first term
$n$ = term number
$d$ = common difference
Use the formula with $a_1=13$ and $d=4$ to obtain:
$a_6 = 13 + 4(6-1)
\\a_6= 13 + 4(5)
\\a_6 = 13 + 20
\\a_6 = 33$
