The Number of Elements in a Finite Set Section 6.2 The Number of Elements in a Finite Set

The Number of Elements in a Set The number of elements in a set A is denoted n(A). Ex. Given n(A) = 4 Since the union doesn’t count a and h twice Notice This leads to Overlap is subtracted

Venn Diagram U B A We can see that So Which leads to – number of elements U 22 B A 5 12 31 We can see that So Which leads to

Survey In a survey of 100 people at a carnival: 40 like cotton candy 30 like popcorn 45 like lemonade 15 like lemonade and popcorn 10 like cotton candy and lemonade 12 like cotton candy and popcorn 5 like all three How many people don’t like lemonade, popcorn, or lemonade? How many people only like popcorn?

Survey U P L n(C) = 40, n(P) = 30, n(L) = 45 C n(U) = 100 set C: cotton candy, set P: popcorn, set L: lemonade U P L 10 8 25 5 7 5 n(C) = 40, n(P) = 30, n(L) = 45 23 C 17 n(U) = 100 8 people only like popcorn. 17 people don’t like lemonade, popcorn, or lemonade.