How can can determine the possible outcomes for these questions?

Question

a. A 40-member club will elect a president and then elect a vice-president. How many possi-ble outcomes are there?

b. A 40-member club will elect a pair of co-presidents. How many possible outcomes are there?



c. Are the answers to parts (a) and (b) the same or different? Explain why they are the same or why they are different.

Answer 1

(a) You can choose the president in 40 ways, and then the vice president in 39. So 40 x 39

(b) The first co-president can be chosen in 40 ways, the second in 39 ways. The order doesnt matter as they are both co-presidents (unlike in (a)) so (40 x 39) / 2

(c) Already answered