Answer:
The constant of proportionality is 0.50
Step-by-step explanation:
The constant of proportionality is the unit ratio between variables.
According to the problem, Marie pays $2.50 for 5 pencils. So, the unit ratio os this would be the constant of proportionaliy. To find it, we just need to divide.
[tex]C=\frac{\$ 2.50}{5 \ pencils}=0.50[/tex]
Therefore, the constant of proportionality is 0.50, which means Marie paid $0.50 per pencil.
