Ziggy sells coffee and donuts, the total number of cofees and donuts ziggy sells today is 100. Ziggy charges 3$ for coffee and 1$ per donut and made 180 today. How many coffees and donuts did he sell?

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)