# Complementary events

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## Lesson details

### Key learning points

- In this lesson, we will look at how we can calculate probabilities for complementary events.

### Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

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### 5 Questions

Q1.

When you roll a fair six-sided dice, it is harder to roll a six than a four.

True

Q2.

In a group of ten people, the probability that at least two were born on the same day of the week is 1.

False

Q3.

There is an even chance of it raining on any given day.

True

Q4.

If I roll a fair six-sided dice, I am more likely to get an even number than an odd number.

True

Q5.

Since a football team can either win, lose, or draw, the probability that they win must be one third.

True

### 5 Questions

Q1.

There are 20 guests at a party. 12 of them are drinking coffee and the rest are drinking tea. What is the probability of selecting one who is drinking tea?

12/20

8

Cannot say.

Option 5

Q2.

There are 18 marbles in a bag. 13 of them are not green. What is the probability of selecting a green marble?

13/18

5%

Cannot say.

Q3.

The probability that it rains tomorrow is 0.4. What is the probability it is sunny?

0.4

0.6

40%

Q4.

There are 100 cars in a car park. 40 of them are yellow. What is the probability of choosing a car that is not yellow?

40%

60

Cannot say.

Q5.

The probability that it will snow tomorrow is 0.05. What is the probability that it won't snow?

5

5%

95

Cannot say.