Given:
Cost price (C.P.) = $4 per box
Selling price (S.P.) = $12 per box
To find:
The percent of markup based on cost.
Solution:
We know that,
[tex]Markup\%=\dfrac{S.P.-C.P.}{C.P.}\times 100[/tex]
On substituting the given values, we get
[tex]Markup\%=\dfrac{12-4}{4}\times 100[/tex]
[tex]Markup\%=\dfrac{8}{4}\times 100[/tex]
[tex]Markup\%=2\times 100[/tex]
[tex]Markup\%=200\%[/tex]
Therefore, the percent of markup based on cost is 200%.