#### Answer

$n=28$

#### Work Step by Step

The n th term of an arithmetic sequence can be calculated as:
$a_n=a_1+d\times(n-1)$
Here: $a_{n}=-76$, $a_1=5$, $d=-3$ and we have to find $n$.
By substituting we get:
$-76=5+(-3)\times(n-1)$
$n-1=\frac{-76-5}{-3}=27$
$n=28$