114(1/2)5?
This sum is very easy only because the probability of heads and tails is the same - 1/2 [4]
what is the probability of getting two consecutive heads in five tosses of an unbiased coin
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UP 0 DOWN 0 0 11
11 Answers
1111Subash there is 4 because the consecutive heads can appear in throws 1 & 2 or 2 & 3 or 3 & 4 or 4 & 5........
62anirudh there is a mistake in your solution...
The question is not exactly 2 consecutive heads..
It should be 1- no consecutive heads.
= 1 - HTHTH - HTTHT - HTTTH - THTHT - THTTH - TTHTH - P(1 head)
= 1 - 6. (1/2)5 - 5. (1/2)5
= 1 - 11 (1/2)5
Check if I missed any cases.
62@anirudh..
even there is a mistake in your cae of exactly 2 consecutive heads..
YOu have missed cases like
HHTHT, HHTTH, THHTH, HTHHT, THTHH, HTTHH
1Nishant Bhaiyya , haven't they asked for exactly two consequetive heads Because no where in the ques it is mentioned about at least two consequetive heads
21SO DO U MEAN TO HHHTH WILL NOT B COUNTED???
[12] [12] HMMMM.......... INTERESTING.......... FIR TO YEH ENGL KA QUESTN HO JAEGA!!! [3]
62Well in any case the question will not be this vague in IIT..
So dont worry..
It is good that we have both the solutions.
But I think it does not mean "exactly" 2 consecutive heads.
In that case, as abhirup has pointed out the case HHTHH will be missed out!
13HH*** 8 cases
THH** 4 cases
*THH* 4 cases
**THH 4 cases
Total no. of favourable cases 20
probability=20/32=5/8
13bhiyaa u have missed the case with no heads ...i mean TTTTT
13= 1 - HTHTH - HTTHT - HTTTH - THTHT - THTTH - TTHTH - TTTTT - P(1 head)
= 1 - 7. (1/2)5 - 5. (1/2)5
= 1 - 12 (1/2)5
=20/32
according to Nishant bhiyaa's method