Page 171 - Math Course 1 (Book 2)

Fundamental Counting Principle

MO. 11 - L6b There are 15,625,000,000 possible outcomes.
There is 1 winning number.
Probability: Fundamental

Counting Principle Answer The probability of winning with
1
one ticket is .
15,625,000,000

Let’s Begin Your Turn!

Find Probabilities
Find Probabilities A. Bob rolls a number cube and tosses a coin. What

is the probability that he will roll an odd number and
Example toss tails?

1
A.
A. Henry rolls a number cube and tosses a coin. 4
What is the probability that he will roll a 3 and B. 1
toss heads? 3
3
First f nd the number of outcomes. C. 8

D. 1

Number Cube 1 2 3 4 5 6
Number Cube

Answer
CoinCoin H T H T H T H T H T H T

There are 12 possible outcomes. B. What is the probability of winning a lottery where
the winning number is made up of 5 numbers from
Look at the tree diagram. There is one outcome 1 to 20 chosen at random? Assume all numbers are
that has a 3 and a head.
eligible each draw.
number of favorable outcomes
P (event) = 1
number of possible outcomes A.
4
1
= 1
12 B. 20
The probability that Henry will C. 1
Answer 1 100
roll a 3 and toss heads is .
12 1
D.
3,200,000
B. What is the probability of winning a raf e where
the winning number is made up of 6 numbers from
1 to 50 chosen at random? Assume all numbers are
eligible each draw.

First, f nd the number of possible outcomes. Use
the Fundamental Counting Principle.

There are 50 choices for the f rst number, 50
choices for the second number, 50 choices for
the third number, and so on.
50 × 50 × 50 × 50 × 50 × 50 = 15,625,000,000

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