23.3 Frequency trees, tables and possibility spaces — Practise with help
Work each question first. Open the hint if you need it, then reveal the working to check.
Warm-up: remember
Try these from memory before opening the answers.
- Work out .
- List the outcomes when a coin is tossed once.
Check
-
-
- H, T.
-
Practise with help
1. A fair coin is tossed and a fair die is rolled. How many outcomes are in the possibility space?
Hint
Pair each coin result with every die result.
Full working
There are outcomes.
2. A frequency tree records 45 learners. 27 travel by bus, and 12 bus users bring lunch. Find the number of bus users who do not bring lunch.
Hint
Subtract the subgroup count from the branch total.
Full working
There are bus users who do not bring lunch.
3. A fair coin is tossed and a fair four-sided spinner numbered 1 to 4 is spun. Find the probability of tails and an even number.
Hint
Pair the two tails outcomes with each of four spinner outcomes. Count the even results.
Full working
There are 8 equally likely pairs. Two have tails and an even number, so the probability is .