ReasoningAges 13-15

Conditional probability tables

Calculate conditional probability from subgroup counts and express the result as a simplified fraction. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 13-15

Conditional probability tables

Take your time. Show your thinking.

1. In a club, 11 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11 s · 7 · Conditional probability ta…
2. In a club, 28 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
28 s · 15 · Conditional probability ta…
3. In a club, 8 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
8 s · 4 · Conditional probability ta…
4. In a club, 11 students play chess, and 8 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11 s · 8 · Conditional probability ta…
5. In a club, 12 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
12 s · 5 · Conditional probability ta…
6. In a club, 14 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
14 s · 5 · Conditional probability ta…
7. In a club, 23 students play chess, and 11 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
23 s · 11 · Conditional probability ta…
8. In a club, 17 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
17 s · 15 · Conditional probability ta…
9. In a club, 11 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11 s · 4 · Conditional probability ta…
10. In a club, 21 students play chess, and 14 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
21 s · 14 · Conditional probability ta…
11. In a club, 10 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
10 s · 7 · Conditional probability ta…
12. In a club, 16 students play chess, and 2 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
16 s · 2 · Conditional probability ta…

12 questions · Seed 104729 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 13-15

Conditional probability tables

Answers and reasoning. Review before teaching.

1. In a club, 11 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
7/11
Out of 11 chess players, 7 play an instrument. Simplifying 7/11 by dividing by 1 gives 7/11.
2. In a club, 28 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
15/28
Out of 28 chess players, 15 play an instrument. Simplifying 15/28 by dividing by 1 gives 15/28.
3. In a club, 8 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
1/2
Out of 8 chess players, 4 play an instrument. Simplifying 4/8 by dividing by 4 gives 1/2.
4. In a club, 11 students play chess, and 8 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
8/11
Out of 11 chess players, 8 play an instrument. Simplifying 8/11 by dividing by 1 gives 8/11.
5. In a club, 12 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
5/12
Out of 12 chess players, 5 play an instrument. Simplifying 5/12 by dividing by 1 gives 5/12.
6. In a club, 14 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
5/14
Out of 14 chess players, 5 play an instrument. Simplifying 5/14 by dividing by 1 gives 5/14.
7. In a club, 23 students play chess, and 11 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11/23
Out of 23 chess players, 11 play an instrument. Simplifying 11/23 by dividing by 1 gives 11/23.
8. In a club, 17 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
15/17
Out of 17 chess players, 15 play an instrument. Simplifying 15/17 by dividing by 1 gives 15/17.
9. In a club, 11 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
4/11
Out of 11 chess players, 4 play an instrument. Simplifying 4/11 by dividing by 1 gives 4/11.
10. In a club, 21 students play chess, and 14 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
2/3
Out of 21 chess players, 14 play an instrument. Simplifying 14/21 by dividing by 7 gives 2/3.
11. In a club, 10 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
7/10
Out of 10 chess players, 7 play an instrument. Simplifying 7/10 by dividing by 1 gives 7/10.
12. In a club, 16 students play chess, and 2 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
1/8
Out of 16 chess players, 2 play an instrument. Simplifying 2/16 by dividing by 2 gives 1/8.

12 questions · Seed 104729 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Conditional probability tables

Take your time. Show your thinking.

1. In a club, 11 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11 s · 7 · Conditional probability ta…
2. In a club, 28 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
28 s · 15 · Conditional probability ta…
3. In a club, 8 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
8 s · 4 · Conditional probability ta…
4. In a club, 11 students play chess, and 8 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11 s · 8 · Conditional probability ta…
5. In a club, 12 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
12 s · 5 · Conditional probability ta…
6. In a club, 14 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
14 s · 5 · Conditional probability ta…
7. In a club, 23 students play chess, and 11 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
23 s · 11 · Conditional probability ta…
8. In a club, 17 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
17 s · 15 · Conditional probability ta…
9. In a club, 11 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11 s · 4 · Conditional probability ta…
10. In a club, 21 students play chess, and 14 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
21 s · 14 · Conditional probability ta…
11. In a club, 10 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
10 s · 7 · Conditional probability ta…
12. In a club, 16 students play chess, and 2 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
16 s · 2 · Conditional probability ta…

12 questions · Seed 104729 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Conditional probability tables

Answers and reasoning. Review before teaching.

1. In a club, 11 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
7/11
Out of 11 chess players, 7 play an instrument. Simplifying 7/11 by dividing by 1 gives 7/11.
2. In a club, 28 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
15/28
Out of 28 chess players, 15 play an instrument. Simplifying 15/28 by dividing by 1 gives 15/28.
3. In a club, 8 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
1/2
Out of 8 chess players, 4 play an instrument. Simplifying 4/8 by dividing by 4 gives 1/2.
4. In a club, 11 students play chess, and 8 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
8/11
Out of 11 chess players, 8 play an instrument. Simplifying 8/11 by dividing by 1 gives 8/11.
5. In a club, 12 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
5/12
Out of 12 chess players, 5 play an instrument. Simplifying 5/12 by dividing by 1 gives 5/12.
6. In a club, 14 students play chess, and 5 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
5/14
Out of 14 chess players, 5 play an instrument. Simplifying 5/14 by dividing by 1 gives 5/14.
7. In a club, 23 students play chess, and 11 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
11/23
Out of 23 chess players, 11 play an instrument. Simplifying 11/23 by dividing by 1 gives 11/23.
8. In a club, 17 students play chess, and 15 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
15/17
Out of 17 chess players, 15 play an instrument. Simplifying 15/17 by dividing by 1 gives 15/17.
9. In a club, 11 students play chess, and 4 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
4/11
Out of 11 chess players, 4 play an instrument. Simplifying 4/11 by dividing by 1 gives 4/11.
10. In a club, 21 students play chess, and 14 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
2/3
Out of 21 chess players, 14 play an instrument. Simplifying 14/21 by dividing by 7 gives 2/3.
11. In a club, 10 students play chess, and 7 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
7/10
Out of 10 chess players, 7 play an instrument. Simplifying 7/10 by dividing by 1 gives 7/10.
12. In a club, 16 students play chess, and 2 of those chess players also play a musical instrument. Given that a student chosen at random plays chess, what is the conditional probability that they also play a musical instrument, as a simplified fraction?
1/8
Out of 16 chess players, 2 play an instrument. Simplifying 2/16 by dividing by 2 gives 1/8.

12 questions · Seed 104729 · Age guidance, not curriculum certification