Finding a missing probability Revision Card

AI generatedProbabilityKey Stage 3

Finding a missing probability.

Probability = favourable outcomes ÷ all outcomes when individual outcomes are equally likely.
A probability lies between 0 and 1; complementary probabilities sum to 1.
Experimental relative frequency estimates probability and can vary between samples.

Example 1

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Subtract both known probabilities from 1.

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Subtract both known probabilities from 1.

Question 1

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Check answer

Subtract both known probabilities from 1.

Question 2

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Check answer

Subtract both known probabilities from 1.

Question 3

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Check answer

Subtract both known probabilities from 1.

Question 4

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Check answer

Subtract both known probabilities from 1.

Question 5

Find .

Exactly one of A, B and C happens

Outcome	A	B	C
Probability

Check answer

Subtract both known probabilities from 1.