Probability

THE PROBABILITY SCALE

P (k) = 0

Impossible

unlikely

Even

Chance

Likely

Certain

0 < P (k) < 1/2

P (k) = 1/2

1/2 < P (k) < 1

P (k) = 1

Tutorial 2

Two coins tossed together.
What is the probability of
getting head and tail on a
toss of two coins?

In the morning, each child chooses to do one of swimming (S), Climbing (C) or
Archery (A).

A class of children go to an activity centre.

In the afternoon, each child chooses to do one of Tennis (T), Volleyball (V) or
Football (F).

Complete the following table to show all the possible combinations of activities.

Two rows have been completed for you.

Jamila has two sets of number cards.

She takes one card from each set.

She multiplies the numbers on her two cards

Show the possible outcomes in the sample space diagram.

2

1

2

Lily has seven cards.

a)

She picks a card at random.

Write down the probability that she picks a card that has a circle on it.

b)

Lily is given one more card.

The probability of picking at random a card with a square on it is now 1/2

Draw a ring around the shape that must be on the new card.

square

circle

triangle

Cannot tell

4

Which one the correct statement?

a)

The probability that a football team a match is 0,6 and the
probability it does not win is 0,4.

b)

The probability that a player scores a goal is 2/8 and the probability
that the player does not score a goal is 3/8

c)

The probability that a fan supports a team is 72% and the
probability that the fan does not support the team is 18 %

d)

The probability that it will rain today is 30%, the probability that it
will not rain is...

1

PROBABILITY

PROBABILITY

Favorable Outcomes

Total Outcomes

THE PROBABILITY SCALE

P (k) = 0

Impossible

unlikely

Even

Chance

Likely

Certain

0 < P (k) < 1/2

P (k) = 1/2

1/2 < P (k) < 1

P (k) = 1

Tutorial 1

Two dice are tossed together once.
What is the chance that the number
of dice will appear more than 10?

Answer:

Total outcomes = 36

n(s)

Favorable outcomes= 3

n(k)

P(K) =

𝒏(𝒌)
𝒏(𝒔)=

𝟑
𝟑𝟔=

𝟏
𝟏𝟐

So, the probability that the number of dice will

appear more than 10 is

𝟏
𝟏𝟐

Tutorial 2

Two coins tossed together.
What is the probability of
getting head and tail on a
toss of two coins?

Answer:

Total outcomes = 4

n(s)

Favorable outcomes= 2

n(k)

P(K) =

𝒏(𝒌)
𝒏(𝒔)=

𝟐
𝟒=

𝟏
𝟐

So, the probability of getting head and tail on a

toss of two coins

𝟏
𝟐

COMMUNICATIVE

Ahmed has two fair six-sided dice. One dice is red and the other
is green.

The faces of the red dice are numbered 1, 2, 3, 4, 5, 6.

The faces of the green dice are numbered 2, 3, 5, 6, 8, 8

Which one the correct statement?
a.
Ahmed is more likely to roll an even number on the red dice

b.
It is impossible for Ahmed to roll a 1 on the green dice

c.
It is certain for Ahmed to roll natural number on the red dice

d.
It is even chance for Ahmed to roll a prime number on
the green dice

In the morning, each child chooses to do one of swimming (S), Climbing (C) or
Archery (A).

A class of children go to an activity centre.

In the afternoon, each child chooses to do one of Tennis (T), Volleyball (V) or
Football (F).

Complete the following table to show all the possible combinations of activities.

Two rows have been completed for you.

A bag contains only green, red, and blue beads.
Pierre takes a bead out of the bag at random.
The probability that the bead is green is double the probability that the bead
is red.

The probability that the bead is blue is 1/3

Complete the table to show the smallest number of each bead that could be
in the bag

COLLABORATIVE

Mia has a box that contains a large of coloured cubes.
She picks a cube at random.
The probabilities of her packing a red, a blue or a green cube are shown in the
table.

a.

Explain how you know that the box must also contain some cubes of
other colours.

b.

Half of the other coloured cubes are yellow. Work out the probability that
Mia picks a yellow cube.

1

Jamila has two sets of number cards.

She takes one card from each set.

She multiplies the numbers on her two cards

Show the possible outcomes in the sample space diagram.

2

1

2

Mike throws a fair six—sided dice.

a)

The scale shows the probability of an event.

Tick (√) all the events that could be represented by the arrow.

Getting an odd number on the dice.

Getting the number 3 on the dice.

Getting a number less than 4 on the dice.

3

b)

Draw an arrow (↑) on the scale to show the probability of getting a 4 or
a 5 on the dice

Lily has seven cards.

a)

She picks a card at random.

Write down the probability that she picks a card that has a circle on it.

b)

Lily is given one more card.

The probability of picking at random a card with a square on it is now 1/2

Draw a ring around the shape that must be on the new card.

square

circle

triangle

Cannot tell

4

Angelique has some building blocks.

The blocks are red or green or yellow or blue.

a)

There are 4 times as many blue blocks as three are green blocks.

Angelique picks a block at random

Complete the table to show the probability of picking each colour.

5

b)

Angelique picks two blocks at random.

Complete the sample space
diagram showing all the
possible outcomes for the
colours of her two blocks.

CRITICAL
THINKING

Which one the correct statement?

a)

The probability that a football team a match is 0,6 and the
probability it does not win is 0,4.

b)

The probability that a player scores a goal is 2/8 and the probability
that the player does not score a goal is 3/8

c)

The probability that a fan supports a team is 72% and the
probability that the fan does not support the team is 18 %

d)

The probability that it will rain today is 30%, the probability that it
will not rain is...

1

Aiko has these number cards.

Aiko chooses two of the number cards.

She multiplies the numbers together.

Find the maximum possible answer she can get.

-8

-4

-2

3

5

2

Manjit sells ice cream.

On Monday,

80 men bought ice cream,
31 of these men chose chocolate flavour,
41% of the women who bought an ice cream chose chocolate flavour.

Tick (√) to show if men or women are more likely to choose chocolate
flavour ice cream.

Men

Women

Show how you worked out your answer.

3

Mike has six cards each labelled with a letter.

He selects a card at random and records the letter on it.

a)

Write down a list of all the possible outcomes

b)

Write down the probability that Mike selects a card that is labelled
with the letter C.

C

H

A

N

C

E

4

CREATIVE
THINKING

Blessy has two bags containing numbered
counters.
She takes one counter at random from
Bag A and another at random from Bag B.

She adds the numbers on her two
counters.

Is she correct? Explain your answer.

Blessy said that, “the probability that
My answer is more than 6 is 2/5”

1

Sita has a fair six-sided dice.

a)

Find the probability of throwing a multiple of 3.

b)

Sita throws a different six-sided dice 120 times.

The table shows her results.

Work out the experimental probability of throwing a
multiple of 3

2

Hassan travels by bus to work every morning.
The bus is either green or blue or yellow.

a)

Calculate the value of x.

b)

Work out the probability that Hassan’s bus is either blue or yellow.

The table shows information about the probabilities of each colour.

3

THANK

YOU