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CHAPTER 7 : PROBABILITY 1
EXERCISE 1
1. A dice is rolled. List the elements in the sample space that satisfy the following
conditions.
(a) An odd number is obtained
(b) A multiple of 3 is obtained
Answer:(a)……………………..
(b)…………………….
2.
N E R 2 9 3 8
DIAGRAM 1
Diagram 1 shows seven cards are labeled. A card is picked at random from the
seven cards.
P = event of selecting a card with a letter
Q = event of selecting a card with a consonant or multiple of 3
List all the elements of
(a) set P
(b) set Q
Answer: (a)……………………….
(b)………………………
3.
P R O B A B I L I T Y
DIAGRAM 2
Diagram 2 shows cards with the letters are put in a box. A card is picked
randomly from the box. The total number of elements in the sample space
is……
Answer:…………………………
…..
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4. Two coins are tossed. List all the elements of the sample space which satisfy
the conditions below.
(a) Two faces are the same
(b) Two faces are different
Answer : (a)………………………
(b) ……………………..
5. A box contains several marbles. Eight of the marbles are blue. If a marble is
2
randomly selected from the box, the probability that it is a blue marble is .
7
Therefore, the total number of marbles in the box is…..
Answer : ………………………
6. Based on the weather record of a region, it is found that the probability of a day
2
being rainy is . Find the expected number of rainy days in a year in the
5
region.
Answer : ………………………..
7. During her study in Ireland, Junaidah received 5 Hari Raya cards her family, 10
Hari Raya cards from her relatives and 15 Hari Raya cards from her friends. If
a Hari Raya card that Junaidah received is selected at random, state the
probability that the Hari Raya card
(a) is sent by her family
(b) is not sent by her relatives
Answer : (a) ……………………..
(b)………………………
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8. A box contains 280 marbles of which 120 are red, and the rest are green or
white. If a marble is picked at random from the box, the probability of picking
1
a green marble is . How many white marbles are there?
4
Answer : ………………………
9. In a group of 115 students, 80 are girls. A further 5 boys then join the group. If
a student is chosen at random from the group, state the probability that the
student chosen is a boy.
Answer : ………………………..
10.
Favourite Colour Red Green Blue
Frequency 75 90 x
TABLE 1
Table 1 shows the results of a survey on the favourite colours of students
in a school.
(a) If a student is chosen from the school, the probability that the student’s
1
favourite colour is red is . Find the value of x.
4
(b) If 100 students were chosen from the school, predict the number of
students whose favourite colour is green
Answer : (a) ……………………..
(b)…………………..
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CHAPTER 7 : PROBABILITY 1
EXERCISE 2
1 . A bag contains 3 blue balls, 4 white balls and 2 green balls. A ball is drawn from
the bag. The number of elements in the sample space is ……….
Answer: ……………………….
2 . A letter is picked at random from the word ‘ P R O B A B I L I T Y ’ . Write the
element of event which the vowel letters are picked.
Answer: ………………………..
3 . A coin is tossed 3 times and the outcomes are recorded. List down the event of
getting 2 heads and a tail.
Answer: ……………………….
4 . A box contains 5 red balls, 7 black balls and 3 yellow balls. If a ball is picked at
random from the box , state the probability that it is red in colour.
Answer: ……………………….
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1
5 . In a quiz, the probability of a team entering semi-final is . If there are 28 teams
4
taking part in the quiz, find the number of teams expected to enter the semi-final.
Answer: ………………………..
1
6 . The probability of an employee coming late to work on Monday is .How
5
many employee are expected to come late to work on Monday if there is a total of
550 employees working on that day ?
Answer: …………………………..
7 . A bag contains a number of balls, 24 of which are green and the remainder blue. If
a ball is chosen at random, the probability that it is green is 0.8. Find the number
of blue balls in the bag.
Answer: ………………………….
8 . A bag contains 36 number cards, some of which are even and the rest odd. The
1
probability of a card, drawn at random being even is . Find the number of odd
6
number cards.
Answer: …………………………..
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9 . A box contains 30 red pens, 50 black pens and the remainder are blue pens. A pen
5
is drawn at random from the box. If the probability of drawing a black pen is ,
16
find the number of blue pens in the box.
Answer: …………………………..
10 . If we choose one number from among the first 30 counting numbers, 1, 2, 3,…, 30
find the probability that the chosen number is divisible by 4.
Answer……………………………
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CHAPTER 7 : PROBABILITY 1
DIAGNOSTIC TEST
1. In a group of 45 students, 35 are girls. A further 5 boys then join the group. If a
student is chosen at random from the group, state the probability that the student is
chosen is a boy
3
A
10
1
B
7
1
C
10
1
D
3
2. A jar contains 270 sweets of orange, lychee and coffee flavour. There are 48 orange
flavoured sweets. If a sweet is picked at random from the jar, the probability of
1
picking a lychee flavoured sweet is . How many coffee flavoured sweets are
3
there ?
A 90
B 132
C 106
D 16
3.
16 18 22 28 60 84
DIAGRAM 1
The diagram 1 shows some number cards. If a card is picked randomly, find
the probability that a multiple of 4 is picked.
2
A
3
1
B
2
1
C
3
1
D
6
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4. During Christmas, Angela sent 6 greeting cards to her friends, 5 greeting cards to
her relatives and 2 greeting cards to her brothers. If a greeting card sent by Angela
is randomly selected , the probability that it was not sent to her brother is
2
A
13
5
B
13
1
C
6
11
D
13
5. A class has 18 boys and k girls. If a student is picked at random from the class,
4
the probability that the student picked is a girl is . Find the value of k.
7
A 18
B 24
C 30
D 42
6. The probability of Hafiz choosing a green coloured shirt is 15%. If Hafiz has
20 shirts, how many shirts are green?
A 3
B 4
C 5
D 6
7. In a group of tourist, 15 of them wear watches. The probability of choosing at
3
random a tourist from the group who wears a watch is . If three tourists who
5
wear watches leave the group, the probability of choosing at random a tourist
who wears a watch is
1
A
22
12
B
25
6
C
11
15
D
25
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8. A box contains 40 red buttons and some white buttons. The probability of
5
choosing at random a white button from the box is . Find the number of
7
white buttons in the box.
A 56
B 100
C 120
D 140
9. In a football match between team P and team Q, the probability that team P
1 2
will win is and the probability that team Q will win is . The probability
2 7
that the match will be a draw is
1
A
7
3
B
7
3
C
14
4
D
21
10. Eggs are categorized into grades A, B and C. A basket contains a total of 100
eggs. If an egg is picked at random from the basket, the probability that the
1 2
eggs are grade A and B are and respectively. Find the number of eggs
4 5
of grade C in the basket.
A 25
B 35
C 40
D 45
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