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Probability Rules and Tree Diagrams — Free MYP5 Mathematics (Standard) Practice Questions
1QuestionSolving Problems using tree diagrams and Venn DiagramsConcept Practice
6 marks~9 minCriterion A
A school survey of 100 students recorded participation in soccer (event A) and basketball (event B). The results are summarised below:
- Students playing only soccer: 30 - Students playing only basketball: 25 - Students playing both sports: 15 - Students playing neither sport: 30
a
State the value of n(A∩B). [1]
b
Calculate n(A) and n(B). [2]
c
Using the formula n(A∪B)=n(A)+n(B)−n(A∩B), calculate n(A∪B). [1]
d
The school requires that more than 65% of surveyed students participate in at least one sport to qualify for additional funding. Justify whether this school meets the requirement. [2]
Solutions
2QuestionSolving Problems using tree diagrams and Venn DiagramsAssessment Practice
2 marks~3 minCriterion C
A school class has 33 students. Let A be the set of students who play football and B the set of students who play basketball, where ∣A∣=15, ∣B∣=10, ∣A∩B∣=5, and ∣A′∩B′∣=3.
Using correct set notation, write one complete sentence that describes the relationship between A∪B and A′∩B′, referring to the universal set U of all students in the class. [2]
Solutions
3QuestionCalculating Combined ProbabilitiesAssessment Practice
4 marks~6 minCriterion D
A quality-control technician at a marble factory tests batches by drawing two marbles without replacement from a bag containing 4 red and 2 blue marbles. After 50 trials, the recorded frequencies are:
Outcome
RR
RB
BR
BB
Frequency
18
16
12
4
a
Calculate the experimental probability of each outcome. [1]
b
Construct a tree diagram showing all possible outcomes with their theoretical probabilities, and calculate the theoretical probability of each outcome. [1]
c
Calculate the theoretical and experimental probabilities of drawing "at least one red" marble, and analyse how closely the experimental results match theory. [1]
d
The factory accepts a batch only if the probability of drawing "no reds" is below 0.10. Using your theoretical probabilities, advise the quality-control technician whether this batch should be accepted, and justify your recommendation using the complementary probability. [1]
Solutions
4QuestionCalculating Combined ProbabilitiesAssessment Practice
8 marks~12 minCriterion B
A quality-control technician at a marble factory tests batches by drawing two marbles without replacement from a bag containing equal numbers of red and blue marbles.
Experiment 1: 2 red, 2 blue marbles Experiment 2: 3 red, 3 blue marbles Experiment 3: 4 red, 4 blue marbles
a
Calculate the probability of drawing a red marble first and a blue marble second for each experiment. Write each answer as a simplified fraction. [3]
b
Deduce a formula for this probability when the bag contains n red and n blue marbles, where n is a positive integer. [2]
c
The factory considers a batch "well-mixed" if the probability of drawing one marble of each colour (in either order) exceeds 21. Advise the factory whether this standard is a useful quality-control threshold, justifying your answer algebraically. [3]