Answer:
Step-by-step explanation:
4 people use all three facilities, then
- 16 - 4 = 12 people use the gym and the track and do not use the pool;
- 9 - 4 = 5 people use the pool and the track and do not use the gym;
- 19 - 4 = 15 people use the gym and the pool and do not use the track.
At least two facilities use 4 + 12 + 5 + 15 = 36 people, 4 of them use all three facilities. Thus, the probability that a randomly selected person which uses at least two facilities, uses all the facilities is