23.3 Frequency trees, tables and possibility spaces — Practise
Work through these independently. Every question gives you a chance to check what you understand.
- A survey has 38 people. 23 use a car and the rest use public transport. Find the public transport count.
- In a two-way table, 17 students are in a group and 9 are girls. How many are boys?
- A coin is tossed and a four-sided die is rolled. How many outcomes are possible?
- Two fair dice are rolled. Find the probability that both show 6.
- Of 50 visitors, 28 are adults. Find the number who are children.
- A table has four counts: 8, 7, 5 and 10. Find the total surveyed.
- A fair coin and a fair coin are tossed. List the outcomes with different results.
- A fair six-sided die is rolled. Find the probability of a result in .
- A group contains 42 people. 19 are in one category and 13 in a second disjoint category. How many are in neither?
- A meal has 3 mains and 2 desserts. How many different main-dessert pairs are possible?
Answers and concise solutions
1. A survey has 38 people. 23 use a car and the rest use public transport. Find the public transport count.
Answer: .
2. In a two-way table, 17 students are in a group and 9 are girls. How many are boys?
Answer: .
3. A coin is tossed and a four-sided die is rolled. How many outcomes are possible?
Answer: outcomes.
4. Two fair dice are rolled. Find the probability that both show 6.
Answer: One of 36 outcomes, so .
5. Of 50 visitors, 28 are adults. Find the number who are children.
Answer: .
6. A table has four counts: 8, 7, 5 and 10. Find the total surveyed.
Answer: .
7. A fair coin and a fair coin are tossed. List the outcomes with different results.
Answer: HT and TH: two outcomes.
8. A fair six-sided die is rolled. Find the probability of a result in .
Answer: .
9. A group contains 42 people. 19 are in one category and 13 in a second disjoint category. How many are in neither?
Answer: .
10. A meal has 3 mains and 2 desserts. How many different main-dessert pairs are possible?
Answer: pairs.