Maths Puzzle: Coins Solution

[TaaastyBurger]

This shit is off the chain!

[LoopyStudios]

It would have been really funny if you told us you couldn't do it with your eyes shut and just ended it there.

[victoriscool1]

This is brilliant!! :D

[retepaskab]

Great trick, but wrong solution, or misleading directions:

"Can you separate the pile into two piles" doesn't allow flipping them.

This way putting coins out of my pocket would also be a solution.

[TheDavsto]

There is something odd about me...there is an algebraic expression that explains this, and I understood that more than I understood this.

[TheDavsto]

There is a great card trick that uses this as the principle behind it.

[cardiganmimi]

@anticorncob6 Ok, so there should be an addendum... "For any finite number of coins..."

[cardiganmimi]

@Montero201414 Yes, trivially. Take 11 coins and flip 'em all over. Then one set has 0 coins, while the other has 11 coins, neither of which have any heads. @Horinius what in the world are you talking about??

[Horinius]

Let's say we're told "there are 5 millions dollars and 5 millions euros in a pile in front of us. We can flip them or we can do whatever we want to them and we are to separate it in 2 piles so there'll be the same amount of $ in each."

I would be expected to have the same amount of dollars at the end after the *separation*. But well, no. There could be 2M $ at the end and 3M vanished into my pocket :)

I might try this trick with my bank or a mafia gang ^_^

[Horinius]

I don't know for the others, but I found your question (given in this video, in the previous video or in the description) was asked in an ambiguous and misleading way. Maybe you did so intentionally so that even intelligent guys can't answer your question? :)

I mean, I would expect the number of heads/whites to be conserved.

[xXxtaureanxXx]

You are truly a genius. 

[anticorncob6]

@BeybladerForLife If you flip them all at once you can!

[yehonataniiii]

What if all of the coins turned out black?

[Montero201414]

What if in a hypothetical situation you have 11 coins, they're all heads would this method still work?

[xramzulx]

3 people don't understand the trick

[Left4Rage]

1. Remember which ones are black.

2. Close eyes.

3. Flip all of the coins you remembered to the other side.

4. Feel how many coins are on the table (should be an even number).

5. If you have 10, put 5 pieces on each side. (8-4, 4-2, 2-1, you're not stupid).

6. Open eyes.

Ta-da!

[BlackWolfRose]

Awesome. Another fun trick to pull on my family!

[miketheman1393]

the second robot wil travel .666 miles the first travel .333 when the meet. let me know if im correct.

[anticorncob6]

@miketheman1393 Yes, and it took me probably more work then you.

Now please hit "reply" so I know you replied and I wouldn't be 2 months late.

[anticorncob6]

Suppose you have an infinite amount of coins, and infinity whites and blacks turn up. You grab infinity coins. In your pile lies infinity white coins and 1 black. In the other lies infinity blacks and infinity whites. You flip all yours over. You get 1 white. In the other pile there are infinity whites. Therefore, this doesn't work. =P

[reubensammut]

what if by some strange chance, all the coins are heads? taking all the coins and flipping them so that there are no heads in either pile isn't really smart

[ijustdontcarenemore]

i was confused because i didnt realise you were going to be flipping them lol, i was wondering how you were going to get 2.5 in each pile haha

[pirsquared99]

Cool puzzle, but I must say that the statement of the puzzle wasn't particularly clear. I was under the impression that you had to leave the coins the way they were, no flipping over. (Of course, you never said that we couldn't flip them over, which just goes to show how easily people jump to conclusions!)

[FHomeBrew]

This reminds me of "subtraction by addition" where you have to calculate the difference between two numbers and you're only allowed to use addition. The method you can find for numbers in base x can be generalized to numbers in any base :-)

[watrick144]

would this work with tails instead of heads?

[singingbanana]

@watrick144 Yup, there's nothing special about heads.

[2MuchGaming]

@singingbanana i find getting head very special...

[Cosmicextry]

@singingbanana Maybe watrick144 was asking if you could still get the same number of heads in each pile (as initially requested) when given the number tails from some random pile. [For example, you see that your black faced coins did not match up (except for the trivial example).] If you don't know the size of the pile, this does make it a slightly different problem. However, it would still be solvable with the same algorithm used in this video (after a simple added step at the beginning).

[livedandletdie]

@singingbanana except there are much more nerve cells in the head.

[Error081688]

Well said, Doc Jim. I talked to a legendary maths professor at my university today for the first time, and I posed the Salem Witch Trials puzzle to him. He figured it out fairly quickly, but he really liked it :).

Also, I've gotten 6 new subscribers just from the shout out in the description :D.

[singingbanana]

@Error081688 I love the Salem Witches puzzle. People may like to dig further back into my videos to find it, it was a puzzle me and my friend Colin made up. And I hope this bump in the comments helps you get more subscribers, it was Tom here that gave me the puzzle, and I love it.

[eXisentZ]

Really clever!

[TyYann]

Great explanation!

[singingbanana]

@TyYann Thanks Yann, tried to explain it without the equations. If people liked this you should check out Yann's channel for more of this sort of thing.

[P4C4N0W5K1]

Mr. Grime would be a cool Maths teacher.

[anticorncob6]

I know a case where this might not work. =P

[2ndAge]

Ok, like you said before you can scam someone. So I did that today and lost one dollar because I forgot to flip! But then I got it back later all thanks to you. =)

[singingbanana]

@2ndAge Haha! Brilliant. But I will be taking 30% of all future earnings.

[2ndAge]

@singingbanana Oh man. Hmm so far did it to 2 people, and waisted the money on a candy. I guess you'll get it later ;D

[kid29a]

haha so simple yet so clever ;)

[GetMeThere1]

I'm totally fascinated by this problem! Thanks for posting it.

[SaiyanKirby]

What's the original name for the game? I've heard it called Othelo and Reversi.

[miketheman1393]

i want a problem simular to ur one fly two trains.

[anticorncob6]

@miketheman1393 Here's one that's even harder.

Suppose a robot is walking. When x seconds go by, he is walking x miles per hour.

Another robot is a mile away facing the first robot. When x seconds go by, it is walking 2x miles per hour.

When will the robots meet?

[iLikeAxe]

Surely if all 11 coins are black, you take 5 and flip them over. Then you have 5 white coins on your side and 6 black ones on the other side?

[RobertBorgersen]

@iLikeAxe If all of them are black, you are told there are zero white pieces. So separate them in to ANY two groups with your eyes shut, and you win.

[PurpleUkuleleGuy]

A SCAM? perhaps one your might try in SCHOOL? Tell me you've tried this on Brian...

[singingbanana]

@PurpleUkuleleGuy That line was entirely for Brian :)

[thomaste33]

How do you know how many heads there are, when your eyes are shut?

[singingbanana]

@thomaste33 The puzzle is, if you are told how many heads there are can you separate them into two piles with the same number of heads in each pile, with your eyes shut.

[tapio2003]

Really clever! Thanks alot!

[toughnerd]

Good to know I was close!

[ffcloud19]

could you show the math involved for this? I love watching your vids man, keep it up! "The best way to stay young is to keep learning," so my aunt said haha

[tottetutte]

@ffcloud19 u stupid?

[singingbanana]

@ffcloud19 Maths isn't just equations, but about logic and problem solving. So this is maths. But this can be described with a couple of equations, and I've put them in the description.

[ffcloud19]

@singingbanana ahhh ok ty...yeah I definitely didn't read the description before posting that comment lol. keep up the vids!

[demon7s]

thanks for uploading this =D

[jlmknight]

thanks for all the vids keep making more :)

[flinkbeder]

awesome video! love your stuff @singingbanana

[MrPointless]

I feel smarter every time I watch a singingbanana video.

[thepianoaddict]

@MrPointless peanut butter jelly time :P