Answer:
The constant of proportionality is 2.5 dollar per cupcake and then the required equation would be [tex]y=2.5x[/tex].
Step-by-step explanation:
Given:
Let the number of cupcakes be represent by [tex]'x'[/tex]
Also let the total cost be represented by [tex]'y'.[/tex]
We know that two proportional quantities are in for;
[tex]y=kx[/tex]
where, k⇒ represents constant of proportionality.
Now we know that;
1 dozen = 12
Half dozen = 6
Now Given:
half dozen cupcakes cost $15.
So Let us substitute [tex]x=6[/tex] and [tex]y=15[/tex] in above equation we get;
[tex]15 =k \times 6[/tex]
Dividing both side by 6 we get;
[tex]\frac{15}{6}=\frac{k6}{6}\\\\k= 2.5 \ \$/cupcake[/tex]
Hence the constant of proportionality is 2.5 dollar per cupcake and then the required equation would be [tex]y=2.5x[/tex].