Given that the cost price (C) is $399 and the selling price (S) of the television is $662.34,
It is asked to find that by how much percentage is the television price marked up.
This can be calculated as follows,
[tex]\begin{gathered} \text{Mark up}=\frac{S-C}{C}\times100 \\ \text{Mark up}=\frac{662.34-399}{399}\times100 \\ \text{Mark up}=\frac{263.34}{399}\times100 \\ \text{Mark up}=0.66\times100 \\ \text{Mark up}=66 \end{gathered}[/tex]Thus, the mark up is 66%.
