Download Probability(6-9b).

COURSE 3 LESSON 6-9
Probability
Express as a fraction the probability that the
outcome for rolling two number cubes has a sum less than 7.
Make a table to find the sample space for rolling two number cubes.
1
2
3
4
5
6
1
(1,1)
(1,2)
(1,3)
(1,4)
(1,5)
(1,6)
2
(2,1)
(2,2)
(2,3)
(2,4)
(2,5)
(2,6)
3
(3,1)
(3,2)
(3,3)
(3,4)
(3,5)
(3,6)
4
(4,1)
(4,2)
(4,3)
(4,4)
(4,5)
(4,6)
5
(5,1)
(5,2)
(5,3)
(5,4)
(5,5)
(5,6)
6
(6,1)
(6,2)
(6,3)
(6,4)
(6,5)
(6,6)
Out of the 36 possible outcomes, the 15 outcomes shown in red
have a sum less than 7.
15
5
So, P(sum less than 7) = 36 , or 12 .
6-9
COURSE 3 LESSON 6-9
Probability
What is the probability (as a fraction) of there being
at least 1 male kitten in a litter of 4 kittens? Express the
probability as a fraction.
6-9
COURSE 3 LESSON 6-9
Probability
(continued)
P(at least one male) =
number of outcomes with at least one male kitten
total number of possible outcomes with four kittens
15
= 16
Substitute.
6-9
COURSE 3 LESSON 6-9
Probability
1. A 6-sided number cube has the numbers 1, 2, 3, 4, 5, and 6
on its faces. What is the probability of rolling a number less than 5?
Write your answer as a fraction and as a percent.
2
2
; 66 %
3
3
2. Find the sample space for tossing two coins. Then find P(0 heads).
HH, HT, TH, TT; 25%
6-9