Probability
Name ___________________________
1. A number cube numbered 1 - 6 is rolled once. List all the possible outcomes.
_____________________________________________________
2. Three quarters are tossed. Make a tree diagram to find the probability of getting exactly 2
heads.
P (exactly 2 heads) = ____________________
3. A tropical ice shaving shop on the beach offers 8 different flavors. Jameera orders a
different flavor on Saturday than she did on Friday.
How many choices did she have on Friday? __________________
How many choices did she have on Saturday? _________________
How many choices in all for the two days? ____________________
4. Five different letters of the alphabet are to be chosen and arranged as security entrance
codes for employees at a Medical Clinic.
How many different codes are possible? _______________________
5. Jean printed whole numbers 1-50 on slips of paper and put them in a hat. He closed his
eyes, reached in the hat and pulled out one of the slips of paper.
What is the probability the number is a prime number? ___________________
What is the probability the number is even or composite? ___________________
What is the probability the number is a multiple of 5? ______________________
6. The spinner shown below is spun twice. What is the probability of landing on pink and then
on orange?
What is the probability of landing on pink and then on orange?
__________________________________
Probability
Answer Key:
1. A number cube numbered 1 - 6 is rolled once. List all the possible outcomes.
Answer: 6 possible outcomes: 1, 2, 3, 4, 5, and 6
2. Three quarters are tossed. Make a tree diagram to find the probability of getting exactly 2
heads.
P (exactly 2 heads) =
3/8
3 out of 8 possibilities have
exactly 2 heads
3. A tropical ice shaving shop on the beach offers 8 different flavors. Jameera orders a
different flavor on Saturday than she did on Friday.
How many choices did she have on Friday?
8 choices
How many choices did she have on Saturday?
How many choices in all for the two days?
7 choices
15 choices
4. Five different letters of the alphabet are to be chosen and arranged as security entrance
codes for employees at a Medical Clinic.
How many different codes are possible?
7,893,600 possible codes
26 * 25 * 24 * 23 * 22 = 7,893,600
5. Jean printed whole numbers 1-50 on slips of paper and put them in a hat. He closed his
eyes, reached in the hat and pulled out one of the slips of paper.
What is the probability the number is a prime number?
16/50 or 8/25
There are 16 prime numbers from 1 to 50
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 39, 41, 43, 47
What is the probability the number is even or composite?
34/50 or 17/25
50 – 16 prime numbers = 34 + 1, since 2 is an even number = 35 – 1,
since 1 is odd and neither prime nor composite = 34 numbers that are
even or composite.
What is the probability the number is a multiple of 5?
There are 10 multiples of 5 from 1to 50
5, 10, 15, 20, 25, 30, 35, 40, 45, 50
10/50 or 1/5
6. The spinner shown below is spun twice. What is the probability of landing on pink and then
on orange?
What is the probability of landing on pink and then on orange?
Answer: 1/8
Landing on pink has a probability of ½
Landing on orange has a probability of ¼
Therefore, the probability of landing
on both pink and orange is
½ * ¼ = 1/8