UNIT 6

1.

Teacher Support Y9A

Probability

Extra Exercises 6.1

The following probability line shows the probabilities of 6 events, A, B, C, D, E and F. A

B

C

0

D

E

F

0.5

1

(a)

(b)

Which event is the most unlikely to occur, but is not impossible?

(c)

Which event is impossible?

(d)

2.

Which event is certain to occur?

Which events are more likely to occur than C?

The diagram shows a jar containing red (R), blue (B) and white (W) balls. One of the balls is taken at random.

R

WW R

W

B RW

RB

W

RRW

RR

WR

W

R

(a)

(b)

3.

What colour is this ball most likely to be?

What colour is this ball least likely to be?

In a game you are given one of the following cards at random:

1

2

3

4

5

6

7

(a)

Are you more likely to be given an odd number or an even number?

(b)

Are you more likely to be given a 7 than a 5 ?

(c)

Are you more likely to be given a number greater or less than 5?

© The Gatsby Charitable Foundation

MEP: Demonstration Project

UNIT 6

1.

Probability

a mint,

(b)

a toffee,

(c)

a chocolate,

(d)

a mint or a toffee,

(e)

not a mint,

(f)

a chocolate or a toffee?

The diagram shows a spinner. What is the probability

that, with one spin, your score is:

(a)

2,

(c)

greater than 2,

(d)

less than 4,

(e)

1

2

1

1,

(b)

3.

Extra Exercises 6.2

A sweet jar contains 10 toffees, 8 mints and 12 chocolates. A sweet is taken at random from the jar. What is the probability that the sweet is:

(a)

2.

Teacher Support Y9A

an even number?

3

6

5

4

1

Ahmed rolls a fair dice 300 times. How many times would he expect to obtain: (a)

6,

(b)

an even number,

(c)

a number greater than 1,

(d)

a number less than 3,

(e)

a 2 or a 5 ?

© The Gatsby Charitable Foundation

MEP: Demonstration Project

UNIT 6

1.

Teacher Support Y9A

Probability

Extra Exercises 6.3

The curved outer surface of a drum is painted red (R),

yellow (Y), purple (P), silver (S) and black (B),

in 5 equal sections.

The drum is spun twice and the colour uppermost noted.

(a)

Copy and complete this list of possible outcomes:

RR

RY

YY

RP

.... ....

RS

.... ....

RB

(b)

YR

.... ....

What is the probability that you obtain:

(i)

2 reds,

(ii)

the same colour on both spins,

(iii) a yellow and a red in any order,

(iii) no yellows.

2.

In a game a card is taken at random from a full pack of 52 playing cards. It is then replaced, and a second card is taken.

Use a tree diagram to calculate the probabilities that:

(a)

(b)

neither card is a diamond,

(c)

one of the cards is a diamond,

(d)

3.

both cards are diamonds,

at least one card is a diamond.

Two fair dice have faces that are numbered,

1, 1, 2, 2, 3, 6

(a)

Draw a table to list the outcomes when the two dice are rolled together and the two scores added to give a total score.

(b)

Calculate the probabilities that the total score on the two dice is: (i)

7,

(iii) an even number,

(v)

a multiple of 3.

© The Gatsby Charitable Foundation

(ii)

greater than 5,

(iv) less than 4

MEP: Demonstration Project

UNIT 6

1.

Probability

Teacher Support Y9A

Extra Exercises 6.4

Sally rolls a dice 300 times.

(a)

(b)

(a)

If you toss a fair coin 10 times, how many heads would you expect to obtain? Toss a coin 10 times and record the number of heads that you obtain.

(c)

3.

Should she be surprised if she obtained 55 sixes?

(b)

2.

How many sixes would you expect her to obtain?

Comment on how your answers to parts (a) and (b) compare.

Two unbiased dice are rolled at the same time. The scores are then multiplied together. (a)

Use a table to list all the possible outcomes.

(b)

If the dice were rolled 72...