Answer:
y = 5
Step-by-step explanation:
22.5(10-y)+27.5y=250
[tex]225 - 22.5y + 27.5y = 250\\\\[/tex]
Combind like terms,
[tex]225 + 5y = 250[/tex]
Subtract 225 from both equations to isolate the variable.
[tex]5y = 25[/tex]
Divide both sides by 5 to isolate the variable and solve it.
[tex]y = 5[/tex]