You use a system of equations x= coffee y= donuts x+y=100 3x+y=180 there’s 3 ways to solve system of equations substitution graphing and elimination. it would be easiest to use substitution here. So you multiply x+y=100 by -1 so it become -x-y=-100. then you combine it with the other equation and get 2x=80 so x=40 which means 40 cups of coffee were sold then you plug it back in to find y. 40+y=100. y=60. y= 60 (donuts). x= 40 (coffee)
