Answer:
9 cats
Step-by-step explanation:
x = cat
y = dog
Set up equations.
x + y = 30
4.5x + 8.5y = 219
Multiply first equation by 4.5 and subtract.
4.5x + 4.5y = 135
-(4.5x + 8.5y = 219)
-4y = -84
y = 21
Substitute this y value into the first equation
x + y = 30
x + 21 = 30
x = 9