Page 422 - Math Smart - 7

9 Somethings always happen.
Think and Share

We say they are certain to happen. If you draw a quadrilateral,
What other property of
quadrilaterals is a certainty? I it has four angles. That is a certainty! four angles
Some things are not certain.

If you toss a coin, it may or may not land heads. It is equally likely to land heads as
to land tails.

18.1.2 Equally likely outcomes

Look at the diagram on the right. Which colour is the pointer
Since each sector of the of this spinner most likely to land on?
spinner is exactly the same
There are 5 possible outcomes: ar^rn, blue, purple, red and
size, the pointer is equally
orange. Each outcome occupies the same area on the circle.
likely to land on any of
We say they have equal chances of occurring. They have equally
the colours.
likely outcomes.
Outcomes that have
an equal chance of The chance of the pointer landing on green is 1 out of 5.
happening are called
The chance of the pointer landing on blue is 1 out of 5.
equally likely outcomes.
The chance of the pointer landing on purple is 1 out of 5.
The chance of the pointer landing on red is 1 out of 5.
9 The chance of the pointer landing on orange is 1 out of 5.
Think and Share

A deck of cards has 52
I
cards. The 52 cards are
divided into 4 suits-2
red suits with hearts and
Suzi has 18 socks in four colours-9 pink, 5 yellow, 3 blue and 1 white. She
diamonds, and 2 black suits
takes one sock from the drawer without looking.
with clubs and spades. Each
suit has 13 cards-A, 2, 3, State whether each of the folllowing statements is true or false. Correct
4, 5, 6, 7, 8, 9, 10, J, Q, K. the false statements.
This means that if you pick a) The sock is most likely white.
a card at random, there are
b) The sock is most likely green.
52 possibilities. What is the
c) The sock is least likely to be white.
chance that you would get
d) The sock is equally likely to be yellow or blue.
a nine of diamonds if you
e) The sock is more likely to be pink than white.
pick a card randomly?
A fair die has 6 faces numbered from 1 to 6. If I throw the die at random,
what is the chance of getting
Randomly chosen objects a) the number 1, b) the number 2, c) the number 3,
are selected by chance or d) the number 4, e) the number 5 and f) the number 6.
without knowing what is
being chosen.

418 UNIT 18 Probability
1