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Combinations Problem Coin Flip

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Senior | Next Rank: 100 Posts
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by relaxin99 » Fri Nov 21, 2008 11:05 am
Hey guys, i just thought of this problem and for some reason im getting an answer that doesnt make sense to me...here it is

If you flip a coin 4 times, what is the probability of getting 2 heads?

I use the coin flip formula as posted by one of the admins

nCk/2^n

4C2/2^4 = 6/16

thats the answer i got, can this actually be correct?

Thanks
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by mals24 » Fri Nov 21, 2008 11:09 am
Yup 6/16 or 3/8 [(6/16) simplified] is the right answer.

Flip the coin 4 times = 2^4 = 16

HHTT
HTHT
HTTH
THTH
THHT
TTHH
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by mals24 » Fri Nov 21, 2008 11:11 am
Btw you can refer the following link Stuart has given a fantastic short cut for "flip the coin" questions.

https://www.beatthegmat.com/coin-flip-qu ... 17911.html
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by jimmiejaz » Fri Nov 21, 2008 11:11 am
yes, this answer is actually correct....
you can cross check by writing all the scenarios.
you will get 6 scenarios.
total cases will be 16 since one coin flip gives 2 cases.....
4 flips will give 2^4 =16.
so, probability will be 6/16.
What if i have not yet beat the beast, I know i will beat it!!!!!!!!
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