A: We want to select one person who works out three days a week. Our probability is simply 12/80 ~~ 15%
B: At least 4 days a week means 4 days, 5 days, or 6 days.
Hence, we have: (9 + 20 + 8)/80 = 46%
C: At least once a week.
Let's find out how many DO NOT work out and subtract that from our sample space. This means they must work out at least once a week.
(80 - 15)/80 = 81%
Keep the inequality sign the same
The right answer is 18.8333333... Or 18 7.5/9
20) Answer is: x=76
21) Answer is x=15
