Answer:
39 - 35 = $4
Explanation:
mean: 19+42+35+40+39 = 175
175/5 = 35
add up all the cost then divide by how many numbers there are.
Median:
list the numbers from lowest to largest
19, 35, 39, 40, 42
then find the number in middle
39
last: 39-35=$4