X=coffee
Y= be donuts
Now create two equations to solve
10x+5y= 16.50
5x+10y= 14.25
Now multiply first equation by -2. To solve both equations
-2(10x+5y=16.50)
-20x-10y=-33
Now add the second equation to solve for x
-20x-10y=-33
5x+10y= 14.25
____________
-5x. = -18.75
Now divide -5 both sides
X= -18.75/-5
X=1.25
Coffee cost $1.25 per cup