Answer:
50 coffees
(and 40 empanadas)
Explanation:
x= coffee y=empanadas
.5x+2y=105
x+y=90
Isolate a variable
x+y=90
x-90= -y
-x+90=y
Plug this in for y in the other equation
.5x+2(-x+90)=105
Solve for x
.5-2x+180=105
-1.5x= -75
x=50
we can stop here but that's lame so let's figure out how many empanadas she sold
we know that x=50 so we can just plug this into either beginning equation and solve for y
50+y=90
y=40