How many different ways could three distinct days of the week be chosen so that at least one of them begins with the letter Upper SS?

To find the number of ways to choose three distinct days of the week such that at least one of them begins with the letter "S," we first identify the days that start with "S": Saturday and Sunday. The total number of ways to choose three distinct days from the seven days of the week is given by the combination ( \binom{7}{3} = 35 ). Next, we calculate the number of combinations that do not include any "S" days, which is ( \binom{5}{3} = 10 ) (choosing from Monday, Tuesday, Wednesday, Thursday, and Friday). Therefore, the number of ways to choose three days that include at least one "S" day is ( 35 - 10 = 25 ).