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 the person uses exactly one of the facilities?

Answer 1

• 0.3 or 30%

Explanation:

Number of people using more than one sport facility:

• 38 - gym and pool
• 31 - pool and track
• 33 - gym and track
• 16 - all three

Since 16 is counted for all three, total number of those using more than one facility is therefore:

• 38 + 31 + 33 - 16*2 = 70

Number of people using exactly one facility is:

• 100 - 70 = 30

Probability of the person using exactly one facility is:

• 30/100 = 0.3 or 30%