The equation [tex]c=8x+5y[/tex] represents the total cost, c, of buying x number of adult tickets and y number of child tickets.
Express [tex]5y:[/tex]
[tex]5y=c-8x.[/tex]
Now divide this equation by 5:
[tex]y=\dfrac{c-8x}{5}.[/tex]
Answer: correct choice is A