Question

A marble is selected from a bag containing eight marbles numbered

1

to

8

.

The number on the marble selected will be recorded as the outcome.

Consider the following events.

Event

A

: The marble selected has an odd number.
Event

B

: The marble selected has a number greater than

3

.

Give the outcomes for each of the following events.
If there is more than one element in the set, separate them with commas.

(a)	Event"AorB":
(b)	Event"AandB":
(c)	The complement of the event B :

Answer 1

A marble is selected from a bag containing 8 marbles numbered 1 to 8. The number on the marble is recorded as outcome.

So, the sample space is -

S = {1,2,3,4,5,6,7,8}

Event A - The marble selected is an odd number

A = {1,3,5,7}

Event B - The marble has selected has a number greater than 3

B = {4,5,6,7,8}

a)-

AorB = AB = all elements in both sets i.e. union of A & B

AB = {1,3,4,5,6,7,8}

b)-

A&B = AB = common elements in both sets i.e. intersection of A & B

AB = {5,7}

c)-

Complement of event B -

B^c = elements not in B but in sample space

B^c = {1,2,3}