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, 17 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?
17 s · 12 · Conditional probability ta…
2. In a club, 9 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?
9 s · 7 · Conditional probability ta…
3. In a club, 8 students play chess, and 3 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 · 3 · Conditional probability ta…
4. In a club, 17 students play chess, and 10 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 · 10 · Conditional probability ta…
5. In a club, 27 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?
27 s · 13 · Conditional probability ta…
6. In a club, 18 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?
18 s · 15 · Conditional probability ta…
7. In a club, 21 students play chess, and 9 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 · 9 · Conditional probability ta…
8. In a club, 22 students play chess, and 9 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 · 9 · Conditional probability ta…
9. In a club, 23 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?
23 s · 12 · Conditional probability ta…
10. 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…
11. In a club, 20 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?
20 s · 11 · Conditional probability ta…
12. In a club, 15 students play chess, and 10 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 s · 10 · Conditional probability ta…

12 questions · Seed 104742 · 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, 17 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?
12/17
Out of 17 chess players, 12 play an instrument. Simplifying 12/17 by dividing by 1 gives 12/17.
2. In a club, 9 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?
7/9
Out of 9 chess players, 7 play an instrument. Simplifying 7/9 by dividing by 1 gives 7/9.
3. In a club, 8 students play chess, and 3 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?
3/8
Out of 8 chess players, 3 play an instrument. Simplifying 3/8 by dividing by 1 gives 3/8.
4. In a club, 17 students play chess, and 10 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?
10/17
Out of 17 chess players, 10 play an instrument. Simplifying 10/17 by dividing by 1 gives 10/17.
5. In a club, 27 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?
13/27
Out of 27 chess players, 13 play an instrument. Simplifying 13/27 by dividing by 1 gives 13/27.
6. In a club, 18 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?
5/6
Out of 18 chess players, 15 play an instrument. Simplifying 15/18 by dividing by 3 gives 5/6.
7. In a club, 21 students play chess, and 9 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?
3/7
Out of 21 chess players, 9 play an instrument. Simplifying 9/21 by dividing by 3 gives 3/7.
8. In a club, 22 students play chess, and 9 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?
9/22
Out of 22 chess players, 9 play an instrument. Simplifying 9/22 by dividing by 1 gives 9/22.
9. In a club, 23 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?
12/23
Out of 23 chess players, 12 play an instrument. Simplifying 12/23 by dividing by 1 gives 12/23.
10. 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.
11. In a club, 20 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?
11/20
Out of 20 chess players, 11 play an instrument. Simplifying 11/20 by dividing by 1 gives 11/20.
12. In a club, 15 students play chess, and 10 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 15 chess players, 10 play an instrument. Simplifying 10/15 by dividing by 5 gives 2/3.

12 questions · Seed 104742 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Conditional probability tables

Take your time. Show your thinking.

1. In a club, 17 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?
17 s · 12 · Conditional probability ta…
2. In a club, 9 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?
9 s · 7 · Conditional probability ta…
3. In a club, 8 students play chess, and 3 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 · 3 · Conditional probability ta…
4. In a club, 17 students play chess, and 10 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 · 10 · Conditional probability ta…
5. In a club, 27 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?
27 s · 13 · Conditional probability ta…
6. In a club, 18 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?
18 s · 15 · Conditional probability ta…
7. In a club, 21 students play chess, and 9 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 · 9 · Conditional probability ta…
8. In a club, 22 students play chess, and 9 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 · 9 · Conditional probability ta…
9. In a club, 23 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?
23 s · 12 · Conditional probability ta…
10. 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…
11. In a club, 20 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?
20 s · 11 · Conditional probability ta…
12. In a club, 15 students play chess, and 10 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 s · 10 · Conditional probability ta…

12 questions · Seed 104742 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Conditional probability tables

Answers and reasoning. Review before teaching.

1. In a club, 17 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?
12/17
Out of 17 chess players, 12 play an instrument. Simplifying 12/17 by dividing by 1 gives 12/17.
2. In a club, 9 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?
7/9
Out of 9 chess players, 7 play an instrument. Simplifying 7/9 by dividing by 1 gives 7/9.
3. In a club, 8 students play chess, and 3 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?
3/8
Out of 8 chess players, 3 play an instrument. Simplifying 3/8 by dividing by 1 gives 3/8.
4. In a club, 17 students play chess, and 10 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?
10/17
Out of 17 chess players, 10 play an instrument. Simplifying 10/17 by dividing by 1 gives 10/17.
5. In a club, 27 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?
13/27
Out of 27 chess players, 13 play an instrument. Simplifying 13/27 by dividing by 1 gives 13/27.
6. In a club, 18 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?
5/6
Out of 18 chess players, 15 play an instrument. Simplifying 15/18 by dividing by 3 gives 5/6.
7. In a club, 21 students play chess, and 9 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?
3/7
Out of 21 chess players, 9 play an instrument. Simplifying 9/21 by dividing by 3 gives 3/7.
8. In a club, 22 students play chess, and 9 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?
9/22
Out of 22 chess players, 9 play an instrument. Simplifying 9/22 by dividing by 1 gives 9/22.
9. In a club, 23 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?
12/23
Out of 23 chess players, 12 play an instrument. Simplifying 12/23 by dividing by 1 gives 12/23.
10. 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.
11. In a club, 20 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?
11/20
Out of 20 chess players, 11 play an instrument. Simplifying 11/20 by dividing by 1 gives 11/20.
12. In a club, 15 students play chess, and 10 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 15 chess players, 10 play an instrument. Simplifying 10/15 by dividing by 5 gives 2/3.

12 questions · Seed 104742 · Age guidance, not curriculum certification