GATE CSE
First time here? Checkout the FAQ!
x
+4 votes
203 views

A coin is tossed thrice. Let X be the event that head occurs in each of the first two tosses. Let Y be the event that a tail occurs on the third toss. Let Z be the event that two tails occur in three tosses.
Based on the above information, which one of the following statements is TRUE?

(A) X and Y are not independent (B) Y and Z are dependent
(C) Y and Z are independent (D) X and Z are independent
 

asked in Numerical Ability by Veteran (41.3k points)   | 203 views

1 Answer

0 votes
so and should be B

  event X =HH _

 event  Y= _ _T      so X and Y are independent  so option A is out

 event Z = 2T 1 H (any order TTH,THT,HTT)  so if X occurs Z can not occur hence X and Z are dependent events so option D is out

event Z = 2T 1 H ( TTH(event Y is not possible hence Y and Z are dependent) ,THT(event Y is possible) ,HTT (event Y is possible)

 consider  choice C and D the question is asked about 2 (exactly 2) tails occur in 3 tosses now if there is a tail in 3rd toss then we need only one tail in first 2 tosses else we need 2 tails   hence they are dependent on each other
answered by Veteran (41.2k points)  
edited by
Can anyone please elaborate i am finding it difficult to understand.


Top Users Mar 2017
  1. rude

    4272 Points

  2. sh!va

    2994 Points

  3. Rahul Jain25

    2804 Points

  4. Kapil

    2608 Points

  5. Debashish Deka

    2244 Points

  6. 2018

    1414 Points

  7. Vignesh Sekar

    1338 Points

  8. Akriti sood

    1246 Points

  9. Bikram

    1246 Points

  10. Sanjay Sharma

    1016 Points

Monthly Topper: Rs. 500 gift card

21,452 questions
26,771 answers
60,972 comments
22,985 users