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If a certain coin is flipped, each of the probabilities that the coin

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MathRevolution
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If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   Updated on: 26 Sep 2016, 05:43
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If a certain coin is flipped, each of the probabilities that the coin will land heads or tails is 1/2. If the coin is flipped 4 times, what is the probability that it will land twice tails up on the 4 flips?

A. 3/8
B. 1/16
C. 1/2
D. 5/8
E. 11/16
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A

Originally posted by MathRevolution on 26 Sep 2016, 05:39.
Last edited by Bunuel on 26 Sep 2016, 05:43, edited 1 time in total.
Renamed the topic and edited the question.
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   27 Sep 2016, 05:04
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MathRevolution wrote:
If a certain coin is flipped, each of the probabilities that the coin will land heads or tails is 1/2. If the coin is flipped 4 times, what is the probability that it will land twice tails up on the 4 flips?

A. 3/8
B. 1/16
C. 1/2
D. 5/8
E. 11/16


If the coin is flipped 4 times then total probability scenarios will be 2^4 times..

Now probability that it will land twice tails up on the 4 flips = 4!/ 2! * 2! - total cases / tails repetition and heads preposition => 6

Possible cases / Total probability = 6/ 2^4 = 3/8.

Option A.
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   28 Sep 2016, 04:19
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==> Just like HHTT, out of 4 flips, the chances of getting 2 heads and 2 tails is 6 (4!/2!2!=6) in HHTT. If so, the chances of getting HHTT is (1/2)(1/2)(1/2)(1/2)=1/16, and 1/16*6=3/8. Therefore the answer is A.
Answer: A
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   24 Jul 2022, 14:04
Expert Reply
MathRevolution wrote:
If a certain coin is flipped, each of the probabilities that the coin will land heads or tails is 1/2. If the coin is flipped 4 times, what is the probability that it will land twice tails up on the 4 flips?

A. 3/8
B. 1/16
C. 1/2
D. 5/8
E. 11/16


4 tails: 1/16
3 tails, 1 head: 4/16
1 tail, 3 heads: 4/16
4 heads: 1/16

Sum: 10/16

What's left? 6/16 = 3/8

Answer choice A
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   08 Aug 2022, 23:23
ThatDudeKnows wrote:
MathRevolution wrote:
If a certain coin is flipped, each of the probabilities that the coin will land heads or tails is 1/2. If the coin is flipped 4 times, what is the probability that it will land twice tails up on the 4 flips?

A. 3/8
B. 1/16
C. 1/2
D. 5/8
E. 11/16


4 tails: 1/16
3 tails, 1 head: 4/16
1 tail, 3 heads: 4/16
4 heads: 1/16

Sum: 10/16

What's left? 6/16 = 3/8

Answer choice A


Hey,
How did you calculate the probability of 3 tails 1 head and 1 head 3 tails?
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   09 Aug 2022, 02:24
If the coin is flipped 4 times then total probability scenarios will be 2^4 times..

Now probability that it will land twice tails up on the 4 flips = 4!/ 2! * 2! - total cases / tails repetition and heads preposition => 6

Possible cases / Total probability = 6/ 2^4 = 3/8
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   09 Aug 2022, 05:41
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samarth1222 wrote:
ThatDudeKnows wrote:
MathRevolution wrote:
If a certain coin is flipped, each of the probabilities that the coin will land heads or tails is 1/2. If the coin is flipped 4 times, what is the probability that it will land twice tails up on the 4 flips?

A. 3/8
B. 1/16
C. 1/2
D. 5/8
E. 11/16


4 tails: 1/16
3 tails, 1 head: 4/16
1 tail, 3 heads: 4/16
4 heads: 1/16

Sum: 10/16

What's left? 6/16 = 3/8

Answer choice A


Hey,
How did you calculate the probability of 3 tails 1 head and 1 head 3 tails?


samarth1222

There are four ways to order four things where three of them are the same and the fourth one is different:
XXXO
XXOX
XOXX
OXXX
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If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   12 Aug 2022, 01:18
since the outcomes can be counted its better to list

or you can use binomial formula
nCr p^r(1-p)(n-r)

= 4c2 (1/2)^2(1/2)^2 = 6(1/4)(1/4) = 3/8
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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink] New post   23 Oct 2023, 18:06
Hello from the GMAT Club BumpBot!

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Re: If a certain coin is flipped, each of the probabilities that the coin [#permalink]
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