Probability-Quiz-5

Probability Quiz-5

Dear Readers,

Probability is an important topic in JEE advanced examination. In this exam, probability carries weightage of 7% of questions. With focused practice good marks can be fetched from this topic .

Q1. An unbiased coin is tossed n times. If the probability that head occurs 6 times is equal to the probability that head occurs 8 times, then n=:

•  7
•  14
•  16
•  19

Solution

Q2.In a game called ‘odd man out’ m(m>2) persons toss a coin to determine who will buy refreshments for the entire group. A person who gets an outcome different from that of the rest of the members of the group is called the odd man out. The probability that there is a loser in any game is:

•  1/2m
•  m/2^m-1
•  2/m
•  None of these

Solution

Q3.  The probability that a teacher will give an unannounced test during any class meeting is 1/5. If a student is absent twice, then the probability that the student will miss at least one test is:

•  4/5
•  2/5
•  7/25
•  9/25

Solution

Q4. Let A and B be two events such that P(A∩B^' )=0.20,P(A^'∩B)=0.15,P(A^'∩B^' )=0.1, then P(A/B) is equal to:

•  11/14
•  2/11
•  2/7
•  1/7

Solution

Q5.Five different games are to be distributed among 4 children randomly. The probability that each child get atleast one game is:

•  1/4
•  15/64
•  21/64
•  None of these

Solution

Q6. Let A and B are events of an experiment and P(A)=1/4,P(A∪B)=1/2, then value of P(B/A^') is:

•  2/3
•  1/3
• 5/6
•  1/2

Solution

Q7. Two numbers are selected randomly from the set S={1,2,3,4,5,6} without replacement one by one. The probability that minimum of the two numbers is less than, 4 is:

•  1/15
•  4/15
•  1/5
•  4/5

Solution

Q8.A sample space consists of 3 sample points with associated probabilities given as 2p,p^2,4p-1. Then the value of p is:

•  p=√11-3
•  √10-3
•  1/4<p<1/2
•  None of these

Solution

Q9.The sum of two positive quantities is equal to 2n. The probability that their product is not less than 3/4 times their greatest product is:

•  3/4
•  1/2
•  1/4
•  None of these

Solution

Q10. If odds against solving a question by three students are 2:1, 5:2 and 5:3, respectively, then probability that the question is solved only by one student is:

•  31/56
•  24/56
•  25/56
• None of these

Solution