What is the solution of -21+15x=6y and -5x+2y=-8

Im sorry but there is an error in the question can you please check it.

If the number of ice cream sandwiches is x

And the number of cookies is y

Then

1.75x + 0.75y = 12.25

and

x + y = 11
y = 11 - x

1.75x + 0.75 (11 - x) = 12.25
1.75x + 8.25 - 0.75x = 12.25
x + 8.25 = 12.25
x = 12.25 - 8.25
x = 4

if x = 4

4 + y = 11
y = 11 - 4
y = 7

x = 4, y = 7