h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Lets say you have 2 coins. Common sense says that there is a lower chance of both of them coming up heads, but the way you describe it, There is a 50/50... Now I am really confused.

There is a 50% chance of the first one coming up heads
There is a 50% chance of the second one coming up heads
There is a 50% chance they both come up heads?
No. Thats not right. There is a 25% chance they both come up heads. There are 2 events, so you need to multiply the probabilities. 1/2*1/2=1/4 So if you flip two coins consecutively, there is a 3/4 chance that the second one will not match the first one. That makes absolutely no sense whatsoever.
Could someone straighten me out?

I think I'll spend the coins in the slots now.

I think i've seen what you've done.

As you correctly said the probability of two heads are 1/4

The probability of two tails is also 1/4. 1/4 + 1/4 = 1/2

'there is a 3/4 chance that the second one will not match the first one.'

I think you've misssed that matching coins includes tails and tails as well as heads and heads

Hope this sorted it out

Yes, I get it now. There is actually a 3/4 chance that they won't both be heads you flip any coins, after you flip the first, if it comes up heads, then there is a 1/2 chance. Thanks.

Yes, I get it now. There is actually a 3/4 chance that they won't both be heads before you flip any coins, after you flip the first, if it comes up heads, then there is a 1/2 chance. Thanks.

(I don't know how to edit a post, I missed a word in my last one)