Download S.CP.B.7 Addition Rule of Probability Scenariosx

Scenarios
1. Grayson and Jade are playing a game. Grayson is winning by two points. He can
increase his score by 15% if he lands on a pink or green space. The spinner for the
game is made of 6 equal sections, red, blue, purple, green, yellow, and pink.
What is Grayson’s probability of spinning a pink or a green?
2. June is rolling a number cube. What is the probability of her rolling a number greater
than 2 or an even number?
3. The probability of a Howard County student owning a bicycle is 0.85, of owning a
scooter is 0.53, of owning both a scooter and bicycle is 0.47. If a Howard County
student is chosen at random what is the probability he/she owns a scooter or a
bicycle?
4. A survey was conducted to collect data on dental hygiene. The results are shown in
the table below. Based on the sample, what is the probability that a person brushes at
least twice a day or flosses their teeth?
Brushes 0-1 times
per day
Brushes 2 or more
times per day
Total
Flosses
10
Does not floss
10
Total
20
46
109
155
56
119
175
5. In Mr. Schaefer’s class of 28 students, 18 are boys and 10 are girls. On the last
geometry test she gave 7 of the girls and 9 of the boys received an A.
What is the probability that a student chosen at random scored an A and was a girl?
What is the probability that a student chosen at random scored an A or was a boy?
How does your solution strategy differ in order to find the solution to these two
questions?
6. Create a scenario where the probability of Event A or Event B occurring is 0.75.
Scenarios - Solutions
1. Grayson and Jade are playing a game. Grayson is winning by two points. He can
increase his score by 15% if he lands on a pink or green space. The spinner for the
game is made of 6 equal sections, red, blue, purple, green, yellow, and pink.
What is Grayson’s probability of spinning a pink or a green?
The probability of landing on any section is
pink or green is
or
. The probability of landing on
.
2. June is rolling a number cube. What is the probability of her rolling a number greater
than 2 or an even number?
Numbers greater than 2: 3, 4, 5, 6
Even numbers: 2, 4, 6
The probability of rolling a number greater than 2 or an even number is
.
1
2 
3 
4 
5 
6 
3. The probability of a Howard County student owning a bicycle is 0.85, of owning a
scooter is 0.53, of owning both a scooter and bicycle is 0.47. If a Howard County
students is chosen at random what is the probability he/she owns a scooter or a
bicycle?
The probability of a student owning a scooter or a bicycle is 0.85 + 0.53 – 0.47 =
0.93.
0.07
0.38
0.47
Bicycle
0.06
Scooter
4. A survey was conducted to collect data on dental hygiene. The results are shown in
the table below. Based on the sample, what is the probability that a person brushes at
least twice a day or flosses his/her teeth?
Brushes 0-1 times
per day
Brushes 2 or more
times per day
Total
Flosses
10
Does not floss
10
Total
20
46
109
155
56
119
175
The probability that a person brushes at least twice a day or flosses his/her teeth is
.
5. In Mr. Schaefer’s class of 28 students, 18 are boys and 10 are girls. On the last
geometry test she gave 7 of the girls and 9 of the boys received an A.
What is the probability that a student chosen at random scored an A and was a girl?
Boy
Girl
Total
Received A
9
7
16
Did not receive A
9
3
12
Total
18
10
28
The probability that a student chosen at random scored an A and was a girl is
What is the probability that a student chosen at random scored an A or was a boy?
Boy
Girl
Total
Received A
9
7
16
Did not receive A
9
3
12
Total
18
10
28
The probability that a student chosen at random scored an A or was a boy is
.
How does your solution strategy differ in order to find the solution to these two
questions?
Answers will vary. Students may identify that question 1 represents the overlap,
whereas question 2 requires the addition rule. Students may or may not choose to
create a two-way table to solve.
6. Create a scenario where the probability of Event A or Event B occurring is 0.75.
Answers will vary.