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, 24 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?
24 s · 14 · Conditional probability ta…
2. In a club, 13 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?
13 s · 2 · Conditional probability ta…
3. In a club, 18 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?
18 s · 4 · Conditional probability ta…
4. In a club, 27 students play chess, and 12 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?
27 s · 12 · Conditional probability ta…
5. In a club, 14 students play chess, and 12 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 · 12 · Conditional probability ta…
6. In a club, 16 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?
16 s · 7 · Conditional probability ta…
7. In a club, 21 students play chess, and 13 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 · 13 · Conditional probability ta…
8. In a club, 24 students play chess, and 12 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?
24 s · 12 · Conditional probability ta…
9. In a club, 18 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?
18 s · 7 · Conditional probability ta…
10. In a club, 22 students play chess, and 13 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?
22 s · 13 · Conditional probability ta…
11. In a club, 30 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?
30 s · 15 · Conditional probability ta…
12. In a club, 4 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?
4 s · 2 · Conditional probability ta…

12 questions · Seed 43 · 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, 24 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?
7/12
Out of 24 chess players, 14 play an instrument. Simplifying 14/24 by dividing by 2 gives 7/12.
2. In a club, 13 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?
2/13
Out of 13 chess players, 2 play an instrument. Simplifying 2/13 by dividing by 1 gives 2/13.
3. In a club, 18 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?
2/9
Out of 18 chess players, 4 play an instrument. Simplifying 4/18 by dividing by 2 gives 2/9.
4. In a club, 27 students play chess, and 12 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?
4/9
Out of 27 chess players, 12 play an instrument. Simplifying 12/27 by dividing by 3 gives 4/9.
5. In a club, 14 students play chess, and 12 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?
6/7
Out of 14 chess players, 12 play an instrument. Simplifying 12/14 by dividing by 2 gives 6/7.
6. In a club, 16 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?
7/16
Out of 16 chess players, 7 play an instrument. Simplifying 7/16 by dividing by 1 gives 7/16.
7. In a club, 21 students play chess, and 13 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?
13/21
Out of 21 chess players, 13 play an instrument. Simplifying 13/21 by dividing by 1 gives 13/21.
8. In a club, 24 students play chess, and 12 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 24 chess players, 12 play an instrument. Simplifying 12/24 by dividing by 12 gives 1/2.
9. In a club, 18 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?
7/18
Out of 18 chess players, 7 play an instrument. Simplifying 7/18 by dividing by 1 gives 7/18.
10. In a club, 22 students play chess, and 13 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?
13/22
Out of 22 chess players, 13 play an instrument. Simplifying 13/22 by dividing by 1 gives 13/22.
11. In a club, 30 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?
1/2
Out of 30 chess players, 15 play an instrument. Simplifying 15/30 by dividing by 15 gives 1/2.
12. In a club, 4 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?
1/2
Out of 4 chess players, 2 play an instrument. Simplifying 2/4 by dividing by 2 gives 1/2.

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Conditional probability tables

Take your time. Show your thinking.

1. In a club, 24 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?
24 s · 14 · Conditional probability ta…
2. In a club, 13 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?
13 s · 2 · Conditional probability ta…
3. In a club, 18 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?
18 s · 4 · Conditional probability ta…
4. In a club, 27 students play chess, and 12 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?
27 s · 12 · Conditional probability ta…
5. In a club, 14 students play chess, and 12 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 · 12 · Conditional probability ta…
6. In a club, 16 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?
16 s · 7 · Conditional probability ta…
7. In a club, 21 students play chess, and 13 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 · 13 · Conditional probability ta…
8. In a club, 24 students play chess, and 12 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?
24 s · 12 · Conditional probability ta…
9. In a club, 18 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?
18 s · 7 · Conditional probability ta…
10. In a club, 22 students play chess, and 13 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?
22 s · 13 · Conditional probability ta…
11. In a club, 30 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?
30 s · 15 · Conditional probability ta…
12. In a club, 4 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?
4 s · 2 · Conditional probability ta…

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Conditional probability tables

Answers and reasoning. Review before teaching.

1. In a club, 24 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?
7/12
Out of 24 chess players, 14 play an instrument. Simplifying 14/24 by dividing by 2 gives 7/12.
2. In a club, 13 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?
2/13
Out of 13 chess players, 2 play an instrument. Simplifying 2/13 by dividing by 1 gives 2/13.
3. In a club, 18 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?
2/9
Out of 18 chess players, 4 play an instrument. Simplifying 4/18 by dividing by 2 gives 2/9.
4. In a club, 27 students play chess, and 12 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?
4/9
Out of 27 chess players, 12 play an instrument. Simplifying 12/27 by dividing by 3 gives 4/9.
5. In a club, 14 students play chess, and 12 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?
6/7
Out of 14 chess players, 12 play an instrument. Simplifying 12/14 by dividing by 2 gives 6/7.
6. In a club, 16 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?
7/16
Out of 16 chess players, 7 play an instrument. Simplifying 7/16 by dividing by 1 gives 7/16.
7. In a club, 21 students play chess, and 13 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?
13/21
Out of 21 chess players, 13 play an instrument. Simplifying 13/21 by dividing by 1 gives 13/21.
8. In a club, 24 students play chess, and 12 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 24 chess players, 12 play an instrument. Simplifying 12/24 by dividing by 12 gives 1/2.
9. In a club, 18 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?
7/18
Out of 18 chess players, 7 play an instrument. Simplifying 7/18 by dividing by 1 gives 7/18.
10. In a club, 22 students play chess, and 13 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?
13/22
Out of 22 chess players, 13 play an instrument. Simplifying 13/22 by dividing by 1 gives 13/22.
11. In a club, 30 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?
1/2
Out of 30 chess players, 15 play an instrument. Simplifying 15/30 by dividing by 15 gives 1/2.
12. In a club, 4 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?
1/2
Out of 4 chess players, 2 play an instrument. Simplifying 2/4 by dividing by 2 gives 1/2.

12 questions · Seed 43 · Age guidance, not curriculum certification