There are 135 people in a sport centre. 73 people use the gym. 59 people use the swimming pool. 31 people use the track. 19 people use the gym and the pool. 9 people use the pool and the track. 16 people use the gym and the track. 4 people use all three facilities. Given that a randomly selected person uses the gym and the track, what is the probability they do not use the swimming pool?

1/9

Step-by-step explanation:

135 in Sport centre: Total

59:swimming pool

31:track

19 both swimming and gym

16 gym and track

4 all three facilities

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

4/36=1/9

Hope this helps!!!

The pythagoream theorem (not sure if I spelled that right...lol): a^2 + b^2 = c^2where c is the hypotenuse and it is the longest side

5^2 + 12^2 = 13^2
25 + 144 = 169
169 = 169(correct)...so it is a right triangle