Question

There are 100 people in a sport centre. 67 people use the gym. 62 people use the swimming pool. 56 people use the track. 38 people use the gym and the pool. 31 people use the pool and the track. 33 people use the gym and the track. 16 people use all three facilities. A person is selected at random. What is the probability that this person uses at least 2 facilities?

Answer 1

Answer:

7/10

Step-by-step explanation:

For a person to use at least two of the facilities means they can use the three facilities as well.

Let n(U) be the total people in the sport centre = 100

n(G) be people that uses gym = 67

n(S) be people that uses swimming pool = 62

n(T) be people that uses track = 56

n(GnP) be gym and pool = 38

n(PnT) be people that use the pool and the track = 31

n(GnT) be people that use the gym and the track = 33

n(GnPnT) be people that use all three facilities = 16

People that uses gym and pool only = n(GnP) - n(GnPnT)

= 38-16

= 22

People that uses pool and track only = n(PnT) - n(GnPnT)

= 31-16

= 15

People that uses gym and track only = n(GnT) - n(GnPnT)

= 33-16

= 17

Total people that uses at least 2 facilities = 16+22+15+17 = 70

Probability that this person uses at least 2 facilities = Total people that uses at least 2 facilities/Total people in the sport centre

Probability that this person uses at least 2 facilities = 70/100 = 7/10