Dependent events · Short practice

Check a final answer, then explain the reasoning on paper. Guest progress stays in this browser; an account saves future checks without overwriting your first result.

Recall

Trees and sampling without replacement — objective 1

Maths4U Original · Short practice

A container has 15 red and 6 blue counters. Two are selected uniformly, one after the other, without replacement.

Find the probability that both are red.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Fresh review variant

Trees and sampling without replacement — objective 1

Maths4U Original · Short practice

A container has 16 red and 3 blue counters. Two are selected uniformly, one after the other, without replacement.

Find the probability that both are red.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Method

Trees and sampling without replacement — objective 2

Maths4U Original · Short practice

A container has 16 red and 3 blue counters. Two are selected uniformly, one after the other, without replacement.

Find the probability of different colours.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Fresh review variant

Trees and sampling without replacement — objective 2

Maths4U Original · Short practice

A container has 17 red and 4 blue counters. Two are selected uniformly, one after the other, without replacement.

Find the probability of different colours.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Apply

Trees and sampling without replacement — objective 3

Maths4U Original · Short practice

A container has 17 red and 4 blue counters. Two are selected uniformly, one after the other, without replacement.

Given that the second counter is red, find the probability that the first was red.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Fresh review variant

Trees and sampling without replacement — objective 3

Maths4U Original · Short practice

A container has 18 red and 5 blue counters. Two are selected uniformly, one after the other, without replacement.

Given that the second counter is red, find the probability that the first was red.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Check understanding

Trees and sampling without replacement — objective 4

Maths4U Original · Short practice

A container has 18 red and 5 blue counters. Two are selected uniformly, one after the other, without replacement.

Find the probability that both are blue.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Fresh review variant

Trees and sampling without replacement — objective 4

Maths4U Original · Short practice

A container has 19 red and 6 blue counters. Two are selected uniformly, one after the other, without replacement.

Find the probability that both are blue.

Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.

Try written exam-style problems →