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M.C.Q

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10 questions · timed · auto-graded

Question 11 Mark
A dice is rolled 600 times and the occurence of the outcomes 1, 2, 3, 4, 5 and 6 are given below:
Outcome
1
2
3
4
5
6
Frequency
200
30
120
100
50
100
The probability of geeting a prime number is:
  1. $\frac{1}{3}$
  2. $\frac{2}{3}$
  3. $\frac{49}{60}$
  4. $\frac{39}{125}$
Answer
  1. $\frac{1}{3}$
Solution:
Prime numbers in 1, 2, 3, 4, 5, 6 are: 2, 3, 5.
Number of times 2, 3, 5 occur = 30 + 120 + 50 = 200
Total number of cases = 200 + 30 + 120 + 100 + 50 + 100 = 600
Required probability $=\frac{\text{Cases when we obtained (2, 3, 5)}}{\text{Total no. of cases}}$
$=\frac{200}{600}=\frac{1}{3}$
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Question 21 Mark
A coin is tosses 1000 times, if the probability of getting a tail is $\frac{3}{8},$ how many times head is obtained?
  1. 525
  2. 375
  3. 625
  4. 725
Answer
  1. 625
Solution:
Probability of getting a tail $=\frac{3}{8}$
⇒ Probability of geeting a head $=1-\frac{3}{8}=\frac{5}{8}$
Also,
Probability of getting a head $=\frac{\text{No.of heads obtained}}{\text{Total no. of trials}}$
$\Rightarrow\ \frac{5}{8}=\frac{\text{No. of heads obtained}}{1000}$
⇒ No. of heads obtainted $=\frac{5}{8}\times1000=625$
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Question 31 Mark
Which of the following cannot be the probability of an event?
  1. $\frac{1}{3}$
  2. $\frac{3}{5}$
  3. $\frac{5}{3}$
  4. $1$
Answer
  1. $\frac{5}{3}$
Solution:
The probability of an event always lies between 0 and 1.
Since $\frac{5}{3}>1,$ it cannot be the probability of an event.
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Question 41 Mark
Two coins are tassed simultaneously. The probability of geeting atmost one head is:
  1. $\frac{1}{4}$
  2. $\frac{3}{4}$
  3. $\frac{1}{2}$
  4. $\frac{5}{4}$
Answer
  1. $\frac{3}{4}$
Solution:
If two coins are tossed simultaneously, then possible cases are HH, TH, HT, TT.
Total number of cases = 4
Number of favorable cases (atmost one head) = (HT, TH, TT) = 3
Now,
Probability of getting atmost one head $=\frac{3}{4}$
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Question 51 Mark
In a football match, Ronaldo makes 4 goals from 10 penalty kicks. The probability of converting a penalty kick into a goal by Ronaldo, is:
  1. $\frac{1}{4}$
  2. $\frac{1}{6}$
  3. $\frac{1}{3}$
  4. $\frac{2}{5}$
Answer
  1. $\frac{2}{5}$
Solution:
Probability that Ronaldo makes a goal 
$=\frac{\text{Number of goal made in all kicks}}{\text{Total number of kicks}}$
$=\frac{4}{10}=\frac{2}{5}$
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Question 61 Mark
A bag contains 50 coins and each coin is marked from 51 to 100. One coin is picked at random. The probability that the number on the coin is not a prime number, is:
  1. $\frac{1}{5}$
  2. $\frac{3}{5}$
  3. $\frac{2}{5}$
  4. $\frac{4}{5}$
Answer
  1. $\frac{4}{5}$
Solution:
Prime numbers from 51 to 100:
53, 59, 61, 67, 71, 73, 79, 83, 89, 97
⇒ Number of prime numbers = 10
⇒ Numver of non-prime numbers = 50 - 10 = 40
Total numbers = 50
Thus, probability of getting no-prime number $=\frac{40}{50}=\frac{4}{5}$
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Question 71 Mark
The percentage of attendance of different classes in a year in a school is given below:
Class
X
IX
VIII
VII
VI
V
Attendance
30
62
85
92
76
55
What is the probability that the class attendance is more than 75%?
  1. $\frac{1}{6}$
  2. $\frac{1}{3}$
  3. $\frac{5}{6}$
  4. $\frac{1}{2}$
Answer
  1. $\frac{1}{2}$
Solution:
Total number of classes = 6
Number of classes having attendance > 75% = VIII, VII, VI = 3
⇒ Required probability $=\frac{3}{6}=\frac{1}{2}$
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Question 81 Mark
The probability of an event of a trial is: 
  1. 1
  2. 0
  3. Less than 1
  4. More than 0
Answer
  1. Less than 1
Solution:
Probability of an event $=\frac{\text{No. of favorable cases}}{\text{Total no. of cases}}$
Since number of favoravle cases can not be greater than total number of cases,
Probability < 1.
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Question 91 Mark
The probability of an impossible event is:
  1. 1
  2. 0
  3. Less than 0
  4. Greater than 1
Answer
  1. 0
Solution:
The probability of an impossible event is always zero since the chances of occurring of that event is zero.
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Question 101 Mark
The probability of a certain event is:
  1. 0
  2. 1
  3. Greater than 1
  4. Less than 0
Answer
  1. 1
Solution:
The chance of occuring of an certain event is always 100%.
Probability $=\frac{\text{No. of favorable cases}}{\text{Total no. of cases}}$
Thus, for a certain event,
Number of favorable cases = Total number of cases
⇒ Probability = 1
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M.C.Q - MATHS STD 9 Questions - Vidyadip