Answer:
a. 12
b. 1/2
Explanation:
Given a meal has 3 choices of meat, 2 choices of fruit, and 2 choices of dessert, you want to know the number of possible meals, and the probability of a meal with no cookie for dessert.
a. Possibilities
As the tree diagram shows, the number of possible meals is ...
(possible meats)×(possible fruits)×(possible desserts)
= 3×2×2 = 12
There are 12 possible lunch options.
b. Cookies
Half the possible dessert choices have no cookie. That is the probability that a lunch will have no cookie:
P(no cookie) = 1/2
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Additional comment
The bottom line of the tree diagram has 6 Cs and 6 Ms. That is, 6 of the 12 options for meals have no cookie.
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