Question

There are 125 people in a sport centre. 59 people use the gym. 70 people use the swimming pool. 55 people use the track. 25 people use the gym and the pool. 30 people use the pool and the track. 17 people use the gym and the track. 6 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?

Answer 1

Answer:

$\frac{97}{125}$

Step-by-step explanation:

As illustrated in the Venn diagram,

We let

U=[The total number of people at the sport center]

This implies that,

n(U)=125

G=[Those who use the gym]

This implies that,

n(G)=59

P=[Those who use the pool]

This implies that,

n(P)=70

T=[Those who use the track]

This implies that,

n(T)=55

a=[Those who use the gym only]

This implies that,

n(a)=59-(6+11+19)=59-36=23

b=[Those who use the pool only]

This implies that,

n(b)=70-(6+19+24)=70-49=21

c=[Those who use the track only]

This implies that,

n(c)=55-(6+24+11)=55-31=14

As shown in the diagram, 7 people do not use any of the facilities

Also, number of people who use gym and track=11+23+19+6+14+24=97

Hence P(a randomly selected person uses the gym and the track,but does not use the swimming pool)

$= \frac{97}{125}$