Lesson 3

Read “Example 1” on page 40 of your textbook. Study the solution on page 41. This example is different than the preceding example about the sports club members. In the textbook example, you are given the total number of children with a pet and you are asked to find different pieces of information. The formula calculation will be slightly different. Note: You would be provided with this formula if you were asked to solve a similar type of problem.
 

The multimedia piece titled Hailey’s Solution demonstrates how Hailey got to the starting point of her solution to the puzzle.

Self-Check 3

Complete the following questions from your textbook.

1. “Practising” questions 5, 6, and 10 on pages 51 to 53
   
   Note: For question 6, using S for swimming, C for cycling, and R for running would be
   
   
    
   n(S) + n(C) + n(R) − n(S ∩ C) − n(C ∩ R) − n(S ∩ R) + n(S ∩ C ∩ R) = n(S ∪ C ∪ R)
   
   Answers
2. “Practising” question 11 on page 33
   
   Answers

Add the following terms to your copy of Glossary Terms:

• intersection
• union
• disjoint
• principle of inclusion and exclusion
• and, or, and not
• empty set

For each new definition in your glossary, be sure to include the appropriate notation.

Add the formula for the principle of inclusion and exclusion to determine the number of elements in the union of three sets.

n(A) + n(B) + n(C) − n(A ∩ C) − n(A ∩ B) − n(B ∩ C) + n(A ∩ B ∩ C) = n(A ∪ B ∪ C)