Answer
$30\ teeth$
Work Step by Step
The relationship of a gear system is:
(no. of teeth in A)(rpm of A) =(no. of teeth in B)(rpm of B).
Now, we have:
$$
80\times 1.25=x\times 3.33\Longrightarrow x=\frac{80\times 1.25 }{3.33}=30\ teeth
.$$