Price she paid, P = $80 .
She sells the bicycle at 1/4 of the price she paid.
Let, buying price is x.
So, as given in question selling price will be x/4.
Also, selling price is given as $80 .
[tex]\dfrac{x}{4}=80\\\\x = \$320[/tex]
Therefore, Steph pay $320 for the bicycle.
Hence, this is the required solution.