1. Tree Diagrams – Unconditional – Higher – GCSE Questions
These questions are the same format as previous GCSE exams.
COPY means they use the exact same numbers as the original GCSE question.
Otherwise, they are clone questions using different numbers.
The worksheets are provided in a variety of sizes.

2. Printing To print handouts from slides -
Select the slide from the left. Then click:
File > Print > ‘Print Current Slide’
To print multiple slides -
Click on a section title to highlight all those slides,
or press ‘Ctrl’ at the same time as selecting slides to
highlight more than one. Then click:
File > Print > ‘Print Selection’
To print double-sided handouts -
Highlight both slides before using ‘Print Selection’.
Choose ‘Print on Both Sides’ and ‘Flip on Short Edge’.

3. GCSE GCSE Edexcel Higher: November 2017 Paper 3, Q12
Xavier has two spinners, spinner A and spinner B.
Each spinner can land on only yellow or black.
The probability that spinner A will land on yellow is 0.6
The probability that spinner B will land on yellow is 0.75
The probability tree diagram shows this information. 1
Xavier has two spinners, spinner A and spinner B.
Each spinner can land on only yellow or black.
The probability that spinner A will land on yellow is 0.6
The probability that spinner B will land on yellow is 0.75
The probability tree diagram shows this information.
Spinner A
Spinner B
Spinner A
Spinner B
0.75
yellow
0.75
yellow
0.6
yellow
0.6
yellow
0.25
black
0.25
black
0.75
yellow
0.75
yellow
0.4
black
0.4
black
0.25
black
0.25
black
Xavier spins spinner A once and he spins spinner B once.
He does this a number of times.
The number of times both spinners land on black is 18
Work out an estimate for the number of time both spinners land on yellow.
Xavier spins spinner A once and he spins spinner B once.
He does this a number of times.
The number of times both spinners land on black is 18
Work out an estimate for the number of time both spinners land on yellow.
(Total for Question 1 is 3 marks)
(Total for Question 1 is 3 marks)

5. GCSE GCSE Edexcel Higher: June 2018 Paper 3, Q4
When a biased 6-sided dice is thrown once, the probability that it will land
on 3 is 0.55
The biased dice is thrown twice.
Lucy draws this probability tree diagram.
The diagram is not correct. 1
When a biased 6-sided dice is thrown once, the probability that it will land
on 3 is 0.55
The biased dice is thrown twice.
Lucy draws this probability tree diagram.
The diagram is not correct.
first throw
second throw
first throw
second throw
0.45
land on 3
0.45
land on 3
0.55
land on 3
0.55
land on 3
0.55
not land on 3
0.55
not land on 3
0.55
land on 3
0.55
land on 3
0.35
not land on 3
0.35
not land on 3
0.45
not land on 3
0.45
not land on 3
Write down two things that are wrong with the probability tree diagram.
Write down two things that are wrong with the probability tree diagram. 1 1 2 2
(Total for Question 1 is 2 marks)
(Total for Question 1 is 2 marks)

7. GCSE Edexcel Higher: November 2017 Paper 3, Q12
Xavier has two spinners, spinner A and spinner B.
Each spinner can land on only yellow or black.
The probability that spinner A will land on yellow is 0.6
The probability that spinner B will land on yellow is 0.75
The probability tree diagram shows this information.
Spinner A
Spinner B
0.75
yellow
0.6
yellow
0.25
black
0.75
yellow
0.4
black
0.25
black
Xavier spins spinner A once and he spins spinner B once.
He does this a number of times.
The number of times both spinners land on black is 18
Work out an estimate for the number of time both spinners land on yellow.
(Total for Question 1 is 3 marks)

8. GCSE Edexcel Higher: June 2018 Paper 3, Q4
When a biased 6-sided dice is thrown once, the probability that it will land
on 3 is 0.55
The biased dice is thrown twice.
Lucy draws this probability tree diagram.
The diagram is not correct.
first throw
second throw
0.45
land on 3
0.55
land on 3
0.55
not land on 3
0.55
land on 3
0.35
not land on 3
0.45
not land on 3
Write down two things that are wrong with the probability tree diagram. 1 2
(Total for Question 1 is 2 marks)

9. GCSE 0.45 0.15 0.3 0.1 Both black = 0.4 x 0.25 = 0.1 (18 times)
Edexcel Higher: November 2017 Paper 3, Q12 1
Xavier has two spinners, spinner A and spinner B.
Each spinner can land on only yellow or black.
The probability that spinner A will land on yellow is 0.6
The probability that spinner B will land on yellow is 0.75
The probability tree diagram shows this information.
Spinner A
Spinner B
0.45
0.75
yellow
0.6
yellow
0.15
0.25
black
0.3
0.75
yellow
0.4
black
0.25
black
0.1
Xavier spins spinner A once and he spins spinner B once.
He does this a number of times.
The number of times both spinners land on black is 18
Work out an estimate for the number of time both spinners land on yellow.
Both black = 0.4 x 0.25 = 0.1 (18 times)
Both yellow = 0.6 x 0.75 = 0.45
18 = 0.1 of total throws
Total throws = 18 x 10 = 180 81
180 x P(Yellow) = 180 x0.45 = 81
(Total for Question 1 is 3 marks)

10. Probabilities should sum to 1
GCSE
Edexcel Higher: June 2018 Paper 3, Q4 1
When a biased 6-sided dice is thrown once, the probability that it will land
on 3 is 0.55
The biased dice is thrown twice.
Lucy draws this probability tree diagram.
The diagram is not correct.
first throw
second throw
0.45
land on 3
0.55
land on 3
0.55
not land on 3
0.55
land on 3
0.35
not land on 3
0.45
not land on 3
Write down two things that are wrong with the probability tree diagram. 1
Probabilities should sum to 1
0.45 and 0.55 reversed on
first branch of second throw 2
(Total for Question 1 is 2 marks)

11. tom@goteachmaths.co.uk Questions? Comments? Suggestions?
…or have you found a mistake!?
Any feedback would be appreciated .
Please feel free to