14. An architect designs a theater with 15 seats in the first row, 18 in the second, 21 in the third, and so on. If the theater is to have a seating capacity of 870, how many rows must the architect use in his design?

A class of 15 students needs to elect a class president, vice president, treasurer, and secretary. How many ways can this be done if each student can serve at most one position?

38) SET UP ONLY: A business has 3 machines that manufacture containers. Together they can make 100 containers per day, whereas the two fastest machines can make 80 containers per day. The fastest machine makes 34 more containers per day than the slowest machine. How many containers can each machine make per day?