Answer:
$0.20
Step-by-step explanation:
When finding the mean, you add up all the numbers, then divide by how many numbers there are. So you add up all the costs and divide them by 7.
Week 1: 3.3
Week 2: 3.1
Then ofcouse, to find the difference you subtract 3.3 by 3.1 and you get $0.20
