The ratio for earning of $37 for 4 hours is,
[tex]\frac{37}{4}[/tex]The ratio for earning of $64.75 for 7 hours is,
[tex]\frac{64.75}{7}[/tex]The relation between earning and time is proportional if both ratios are equal to each other.
Multiply the ratios such that denominator is same for both the cases.
[tex]\frac{37}{4}\cdot\frac{7}{7}=\frac{259}{28}[/tex]and
[tex]\frac{64.75}{7}\cdot\frac{4}{4}=\frac{259}{28}[/tex]So both ratios are equal to each other. Hence relation between time and earning is proportonal relationship.
