Probability

Study Material (PDF)
Self Assesment
Study Material (PDF)
Self Assesment

Click on each question to see answer & solution.

Question No: #11

An unbiased die is thrown seven times. What is the probability of getting number `5` exactly 2 times?
Ans: `(7/12)(5/6)^5`
SEE SOLUTION

Question No: #12

An unbiased coin is tossed three times in succession, then the probability of getting just one head is --
(a) `1/2`, (b) `5/8`, (c) `3/4`, (d) `3/8`
Ans: (d) `3/8`
SEE SOLUTION

Question No: #13

A coin is tossed 4 times, if head occurs on first three tosses, then the probability of getting head on fourth toss is -
(a) `1/2` (b) `1/3` (c) `1/4` (d) `3/4`
Ans: (a) `1/2`
SEE SOLUTION

Question No: #14

An unbiased coin is tossed three times. Find `P(E | F)` where `E`: Head in third toss, & `F`: Head in first two toss.
Ans: `1/2`
SEE SOLUTION

Question No: #15

Let `X` represents the difference between number of heads and number of tails obtained when a coin is tossed 6 times. What are possible values of `X`?
Ans: `X = {0,2,4,6}`
SEE SOLUTION

Question No: #16

What is the probability of two numbers randomly selected from the first 15 natural numbers both being odd, if their sum is even?
Ans: `4/7`
SEE SOLUTION

Question No: #17

A student makes random guesses for 8 true/false questions. What is the probability of getting 5 correct answer?
Ans: `93/2^8`
SEE SOLUTION

Question No: #18

What is the probability of getting 5 Sundays in the month of January?
Ans: `3/7`
SEE SOLUTION

Question No: #19

The probability that there will be 53 Sunday in a year of the 22nd century chosen at random is --
(a) `3/28`, (b) `2/28`, (c) `7/28`, (d) `5/28`
Ans: (d) `5/28`
SEE SOLUTION

Question No: #20

What is the probability that in a family of 5 members, exactly two members have birthday on Sunday?
Ans: `\frac{(10 \times 6^3)}{7^5}`
SEE SOLUTION