For this you can multiply the bill by the tip, in decimal form, that is
[tex]\begin{gathered} 15\text{ \%}=0.15 \\ \text{ So,} \\ 42.50\times0.15=6.375 \\ \\ \end{gathered}[/tex]
Therefore, the amount of tip will be $6.375. And of the answers given, none is correct.
