# Complementary Events

## Interactive practice questions

Are the following events complementary?

a

Event A: Selecting a positive number.

Event B: Selecting a negative number.

Complementary

A

Not complementary

B

Complementary

A

Not complementary

B
b

Event A: Drawing a red card from a standard deck of cards (no jokers).

Event B: Drawing a black card from a standard deck of cards (no jokers).

Complementary

A

Not complementary

B

Complementary

A

Not complementary

B
c

Event A: Drawing a club from a standard deck of cards (no jokers).

Event B: Drawing a spade from a standard deck of cards (no jokers).

Complementary

A

Not complementary

B

Complementary

A

Not complementary

B
d

Event A: Rolling a number greater than 3 on a die.

Event B: Rolling a number less than 3 on a die.

Complementary

A

Not complementary

B

Complementary

A

Not complementary

B
Easy
Approx a minute

The probability that a certain event will occur is $\frac{4}{5}$45. Find the probability that the complementary event will occur?

The probability of an event is $0.64$0.64. What is the probability of the complementary event?

A biased coin is flipped, with heads and tails as possible outcomes. Calculate P(heads) if P(tails) is 0.56.

### Outcomes

#### S5-4

Calculate probabilities, using fractions, percentages, and ratios