Question

Thirty-three cities were researched to determine whether they had a professional sports team, a symphony, or a children's museum. Of these cities, 17 had a professional sports team, 15 had a symphony, 14 had a children's museum, 9 had a professional sports team and a symphony, 6 had a professional sports team and a children's museum, 6 had a symphony and a children's museum, and 3 had all three activities.

Complete parts a) through e) below.

a) How many of the cities surveyed had only a professional sports team?   

b) How many of the cities surveyed had a professional sports team and a symphony, but not a children's museum?

c) How many of the cities surveyed had a professional sports team or a symphony?   

d) How many of the cities surveyed had a professional sports team or a symphony, but not a children's museum?   

e) How many of the cities surveyed had exactly two of the activities?   

Simplify your answers.

Answer 1

a) The number of cities that had only a professional sports team can be found by subtracting the number of cities that had a professional sports team and a symphony, the number of cities that had a professional sports team and a children's museum, and the number of cities that had all three activities from the total number of cities:

33 - (9 + 6 + 3) = 15 cities had only a professional sports team.

b) The number of cities that had a professional sports team and a symphony, but not a children's museum can be found by subtracting the number of cities that had all three activities from the number of cities that had a professional sports team and a symphony:

9 - 3 = 6 cities had a professional sports team and a symphony, but not a children's museum.

c) The number of cities that had a professional sports team or a symphony can be found by adding the number of cities that had a professional sports team, the number of cities that had a symphony, and then subtracting the number of cities that had both:

17 + 15 - 9 + 14 - 6 + 3 = 34 cities had a professional sports team or a symphony.

d) The number of cities that had a professional sports team or a symphony, but not a children's museum can be found by subtracting the number of cities that had all three activities from the answer to part c:

34 - 3 = 31 cities had a professional sports team or a symphony, but not a children's museum.

e) The number of cities that had exactly two of the activities can be found by adding up the number of cities that had a professional sports team and a symphony, the number of cities that had a professional sports team and a children's museum, and the number of cities that had a symphony and a children's museum, and then subtracting twice the number of cities that had all three activities:

9 + 6 + 6 - 2(3) = 15 cities had exactly two of the activities.