Q1 . What is the probability of picking a red ball from a basket containing 3 black,4 blue and 2 red balls?

1. 2/9

2. 1/2

3. 1/3

4. 1/8

Check Answer

Correct Answer is

2/9

SOLUTION

Total number of balls in the basket=2+3+4=9

Number of balls that are red=2

probability of picking the red ball

=2/9

Q2 . What is the probability of getting an even number divisible by 3 in a throw of dice?

1. 2/6

2. 1/2

3. 1/6

4. 1/3

Check Answer

Correct Answer is

1/6

SOLUTION

Total possibilities in a throw of dice is 6

Total even numbers in a throw would be 2,4,6

Only six is an even number divisible by 3

Probability is

1/6

Q3 . If an unbiased coin is tossed thrice then what is the probability of getting a head thrice?

1. 1/4

2. 2/3

3. 1/2

4. 1/8

Check Answer

Correct Answer is

1/8

SOLUTION

The probability of getting a head is 1/2

We are looking for a probability of heads AND heads AND heads

1/2x1/2x1/2

=1/8

Q4 . If two unbiased coins are thrown then what is the probability that a head and a tail will appear?

1. 1/4

2. 1/2

3. 3/4

4. 1/8

Check Answer

Correct Answer is

1/2

SOLUTION

The probability of getting a head or tail in a toss of a coin is 1/2

The probability of getting a head or tail would be

head AND tail OR tail AND head

1/2x1/2+1/2x1/2

1/4+1/4

2/4=1/2

Q5 . What is the probability of getting two numbers picked from the first 20 integers such that both the numbers have an odd product.The numbers picked have to be unique?

1. 9/38

2. 1/2

3. 12/37

4. 20/90

Check Answer

Correct Answer is

9/38

SOLUTION

In th first 20 numbers there are 10 odd and 10 even numbers

Product of two odd numbers will be odd

Pick an odd number then pick another odd number

10/20x9/19=

9/38

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Probability solved problems part -1

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