Answer: There are 20 people who had burgers while 10 had sandwiches.
Step-by-step explanation: First you set up the two equations:
x+y=30
3x+2y=80
Then you start the elimination process by making either the x or the y the opposite of one another (I’m using y):
-2x+-2y=-60
3x+2y=80
Eliminate!
x=20
Plug in x to check and solve for y!