[Math riddle] Where did the last bit go ?!

[yogg]

For the purpose of the riddle, it takes place in a world where 10 bits (1000 satoshi) will buy you a beer. 
Will you find the answer ? Is there any answer to this problem at all ? Let's try !

There is a marine boat coming back from a long time sailing on the sea.
To celebrate, 3 friends decided to go have a good, fresh beer in a pub.
They enjoyed it, and had a great time. At some point, one of them asked the waiter for the bill.
The waiter brought it, and the bill was 30 bits. It's 10 bits for a beer, so each of them gave 10 bits.
But, the pub manager said to the waiter that they're marines, they're good guys helping the country, and gave a 5 bits discount on the bill.

The waiter brought 5 bits back, but it can't be split evenly among the 3 of them so they decided to get 1 bit back for each of them, and leave 2 bits as a tip to the waiter.

So .. If each of them paid 10 bits and got 1 back, one beer costed 9 bits.

3*9 = 27 bits.

Plus the waiter's tip :

27 + 2 = 29 bits.

Where did the last bit go ?!

Enjoy

[Watoshi-Dimobuto]

Total beer cost:
10*3=30
Less: discount: 30-5=25

Net cost: 9*3=27
Less: waiter's tip: 27-2=25

What is the problem ?  

[yogg]

Total beer cost:
10*3=30
Less: discount: 30-5=25

Net cost: 9*3=27
Less: waiter's tip: 27-2=25

What is the problem ?  

Your net cost is wrong here.
The waiter's tip should be added to 27, which gives us 29.

Still, they paid 30..

[Watoshi-Dimobuto]

Total beer cost:
10*3=30
Less: discount: 30-5=25

Net cost: 9*3=27
Less: waiter's tip: 27-2=25

What is the problem ?  

Your net cost is wrong here.
The waiter's tip should be added to 27, which gives us 29.

Still, they paid 30..

nope.

net cost is 27 (not 29 or 25)
Net paid = 25 (excluding tip because tip is paid out of their pocket and not from discount)


You can do the same i did in another way:

Paid = 30

Cost per person = 9
Net cost = 27
Add: discount 5
Total : 32
Then they paid the waiter's tip : 2
Total = 30

i think this one is more sensible.

[duke1839]

No missing bit.

30 total bits

25 to the bartender

2 to the waiter

3 to the marines

25 + 2 + 3 = 30


The reason this confuses some people is because they do this 27 + 2 = 29   instead of 27 - 2 = 25 

[gordoh]

Yea the problem here is the wording. That's why it seems that there is a bit missing lol. I have heard of this math problem before.

[Vod]

Yea the problem here is the wording. That's why it seems that there is a bit missing lol. I have heard of this math problem before.

The problem is also how you calculate it.  The wording makes you calculate wrong.

(a+b)*c

is different than

a+(b*c)

[gordoh]

Yea the problem here is the wording. That's why it seems that there is a bit missing lol. I have heard of this math problem before.

The problem is also how you calculate it.  The wording makes you calculate wrong.

(a+b)*c

is different than

a+(b*c)

Exactly!!! 

[yogg]

Thanks all for your replies 

Yah, it's a known math problem, but I guess the Bitcoin forum isn't the best place to post that kind of things.
People know too well how to calculate here.

When I told that to some of my friends, they took some monopoly bills to physically touch the "money" so they see where that last unit has gone lol