In a programming assignment, the instructor found that 26 people take 2-3 hours, 34 people take 3-4 hours, and 20 people take more than 4 hours to finish an assignment. What is the probability that the assignment can be done in 4 hours or less?
Number of people who finished the assignment in 4 hours or less = 26 + 34 = 60
Total number of people = 26 + 34 + 20 = 80
Probability that the assignment is finished in 4 hours or less = 6080 = 0.75.