Make a biased coin unbiased

YOu have a coin which is biased say 75%chance of heads. How do use this coin for an unbiased decision! (can it be done?)

9 Answers

1
Vishal SC ·

can it be done!

1
Vishal SC ·

this could be interesting !!!

62
Lokesh Verma ·

Actually it can be done!
Hint: You need two tosses only!!!

1
Vishal SC ·

if "the first toss is head and second tail" or "both heads" then we take it as head.

Otherwise, we take it as tails.

Will it be correct?

62
Lokesh Verma ·

No it wont...

actually the first way will give a probability of p(1-p) + p2

second way will give a probability of (1-p)p + (1-p)2

These are not equal.

But one more hint.... you came so close to the answer and still did not get it correct. I feel bad.. I mean u are really really close!

1
Vishal SC ·

hmm... i see my mistake.. but from your solution and the way you have written it, i figured out the right answer :D

I hope i am right this time...

tail-head. We call tail

Head-tail. we call head.

But what do we do of the other tow cases i cant figure out.
I mean what if we get head-head. or tail-tail!

1
Vyom Parashar ·

wow, this was a pretty exciting question. New and unseen. I guess nishant bowled me with this one... Thanks buddy for this wonderful question. I will take it as one of the best i have ever seen.

For Vishal's doubt. You will retoss in the two cases! *H-H and T-T.

Simple :)

Wow i cant still stop praising this question!

62
Lokesh Verma ·

Bingo vishal and vyom. Nice to know that u loved this question :)

1
Who Am I ·

this is a good question indeed :)
i was thiking and thinking and could not think

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