#### 11th Standard Maths Introduction To Probability Theory English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Maths

Time : 00:10:00 Hrs
Total Marks : 10

10 x 1 = 10
1. A number is selected from the set {1,2,3,...,20}.The probability that the selected number is divisible by 3 or 4 is

(a)

${2\over5}$

(b)

${1\over8}$

(c)

${1\over2}$

(d)

${2\over3}$

2. A bag contains 5 white and 3 black balls. Five balls are drawn successively without replacement. The probability that they are alternately of different colours is

(a)

${3\over 14}$

(b)

${5\over 14}$

(c)

${1\over 14}$

(d)

${9\over 14}$

3. A bag contains 6 green, 2 white, and 7 black balls. If two balls are drawn simultaneously, then the probability that both are different colours is

(a)

${68\over 105}$

(b)

${71\over 105}$

(c)

${64\over 105}$

(d)

${73\over 105}$

4. If two events A and B are independent such that P(A)=0.35 and $P(A\cup B)=0.6$ ,then P(B) is

(a)

${5\over 13}$

(b)

${1\over 13}$

(c)

${4\over 13}$

(d)

${7\over 13}$

5. In a certain college 4% of the boys and 1% of the girls are taller than 1.8 meter. Further 60% of the students are girls. If a student is selected at random and is taller than 1.8 meters, then the probability that the student is a girl is

(a)

${2\over 11}$

(b)

${3\over 11}$

(c)

${5\over 11}$

(d)

${7\over 11}$

6. The probability of two events A and B are 0.3 and 0.6 respectively. The probability that both A and B occur simultaneously is 0.18. The probability that neither A nor B occurs is

(a)

0.1

(b)

0.72

(c)

0.42

(d)

0.28

7. A bag contains 5 black balls, 4 white balls and 3 red balls. If a ball is selected at random, the probability that it is black or red ball is

(a)

$\frac { 1 }{ 3 }$

(b)

$\frac { 1 }{ 4 }$

(c)

$\frac { 5 }{ 12 }$

(d)

$\frac { 2 }{ 3 }$

8. A box contains 10 good articles and 6 with defects. One item is drawn at random. The probability that it is either good or has a defect is

(a)

$\frac { 64 }{ 64 }$

(b)

$\frac { 49 }{ 64 }$

(c)

$\frac { 40 }{ 64 }$

(d)

$\frac { 24 }{ 64 }$

9. The probability that in a year of 22nd century, chosen at random there will be 53 Sundays is

(a)

$\frac { 3 }{ 28 }$

(b)

$\frac { 2 }{ 28 }$

(c)

$\frac { 7 }{ 28 }$

(d)

$\frac { 5 }{ 28 }$

10. If A and B are two events such that $P(A\cap B)=\frac { 7 }{ 10 }$ and P(B) = $\frac { 17 }{ 20 }$ , then P(A/B) =

(a)

$\frac { 14 }{ 17 }$

(b)

$\frac { 17 }{ 20 }$

(c)

$\frac { 7 }{ 8 }$

(d)

$\frac { 1 }{ 8 }$