CAMBRIDGE CHECKPOINT MATHEMATICS CLASS 8 EX 15.2 ANSWERS_2013 EDITION
EX 15.2 SOLUTIONS
1 Ahmad throws a dice. Find the probability that it is: a a 2
b not a
c not a 5
d not a multiple of 3.
2 Maha writes the letters of the word 'MATHEMATICS' on separate cards.
She takes one card at random. Find the probability that the letter on the card is: a an M
b not an M
c S or T
d B e before J in the alphabet.
3 In the game of 'Scrabble' there are 100 tiles. Each has one letter or a blank.
The table shows the numbers of tiles with vowels.
One tile is taken at random. Find the probability that it is:
a A
b U
c not O
d a vowel
e not a vowel.
4 Harsha chooses a number at random from this grid. Find the probability that the number she chooses is: a 27
b in the bottom row c in the first column
d not in the last two columns.
Harsha chooses another number at random from the Find the probability that her number is: e less than 10
f more than 10 g not 10
h more than 20.
5 This is a calendar for April in one year.
Anders chooses a day at random. Find the probability that the day he chooses is:
a a Monday b not a Monday c 16 April
d not 16 April
e a Thursday or a Friday.
6 Zalika chooses one day of the year 2015 at random.
a What is the probability that it is: i 5 August ii not 5 August iii in August iv not in August?
b Suppose she chose a day in 2016 instead of 2015. Which probabilities in part a would be greater
now?
7 A computer generates a single-digit random number. It could be any number from 0 to 9.
Find the probability that it is:
a 0 b not 0 c a multiple of 3 d 3.5 e less than 7.
8 A computer generates a two-digit number random number. It can be any number from 00 to 99.
Find the probability that it:
a is 99 b is not 99 c has no 9s in it d has at least one 9 in it.
9 When Razi throws two coins there are four equally likely outcomes.
H = head
T = tail
a How many of these four outcomes will give:
i two heads ii one head and one tail iii two tails?
b If two coins are thrown, what is the probability of getting:
i two heads ii one head and one tail iii two tails?
10 Sasha tosses three coins together.
a Explain why there are eight equally likely outcomes.
b Find the probability that there will be:
i three heads ii three tails iii two heads and one tail iv two tails and one head.
