I'm stumped; impossible math problem?

 I'm really stumped here everyone... I everyone I talk to has no idea about this either, is they're something we're missing? 
 
 3 Guys order a pizza.   

The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.

$10 + $10 + $10 = 30

When the delivery guy goes back to the pizzaria, his boss says that he over charged them for the pizza, and to give them 5 dollars back (In loonies, or dollar bills depending on where you're from).

The delivery guy goes back to the 3 guys and returns the 5 dollars.

$30 - $5 = 25

The 3 guys give the delivery guy a 2 dollar tip and they each take 1 dollar back.

$1 + $1 + $1 + $2 = $5

This means that they only spent 9 dollars on the pizza each, instead of 10.

$9 + $9 + $9 = $27

Plus the 2 dollars they gave as a tip.

$27 + $2 = 29

Where did the other dollar go? 

the pizza delivery guy pocket that dollar.

This seems like a trick question.  I'm trying to think this out.  At the moment that the delivery noticed that the 3 guys were overcharged, the cost of the pizza was $25.  Meaning that each guy ended up really paying only 8.33 each (approximately).  8.33 x 3 = 25 bucks.  They end up giving the delivery duder 2 bucks,  Bringing the total paid to 27 bucks.  They kept the other 3.   
 
It's a trick question.  It's basing the math around each person paying $10 as opposed to each person paying for a total of $30.  When the 5 bucks is removed the amount each person needed to pay got dropped as opposed to being 10.  I'm not positive about this, since technically they still gave the pizzeria 10 each to begin with, but something's definitely intentionally wrong with that problem. 

Jeez, they way underpaid the tip... should be closer to $4.50 for the tip....

found it. 
this is an accounting question, not a math problem
 
be back in a minute with the answer
 
EDIT FOR ANSWER:
 
 The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.
its (0 + 30 = 30) for the pizza guy (30 - 30 = 0) for the guys
 
 
 The delivery guy goes back to the 3 guys and returns the 5 dollars.
then (30 - 5 = 25) for the pizza guy and (0 + 5 = 5) for the guys
  

 The 3 guys give the delivery guy a 2 dollar tip
then (25 + 2  = 27) for the pizza guy and (5 - 2 = 3) for the guys 
 
soo...the cost of the pizza now is 27$ and they have their 3 dollars left in their account.
 
@TimesHero:
your problem was that you were working backwards whereas you need to follow the transactions as they happen

The new price of the pizza is 27 (Given that originally it was 30, less the overcharge 5 plus 2 tip). Over 3 people that is 3x9. So given that they each originally gave out 10 they are each owed 1 so when the delivery man gives them 5 they each take 1 (to make 3) and give him 2. That makes their total 9 (10-1) and 9x3 is 27 which is the new price of the pizza (given originally it was 30, less overcharged 5 and 2 tip).

I think thats right.

3 guys ended up giving a $2 tip, right? One of those guys paid $1 less than the rest. Not sure which one tho.
 
it's $10 + $10 + $9, not $9 + $9 + $9... that tip didn't magically come from nowhere. ;) 

Was the tip counted in the initial $30?

It seems to me that the $27 already includes the tip.  
 
The pizza cost $25. They tipped him $2 and kept the other $3. 
 
25 + 2 + 3 = 30.  
 
Edit: Honestly, they probably should've just tipped him the $5, and saved everyone this headache. 

It all seems accounted for to me. He gave them $5 back, but they tipped him $2, so between the three of them, they spent $27 and have $3 back from the delivery guy. $27 + $3 = $30.

they didn't actually pay $9 each, the pizza was $25 and they each got back a dollar (making the dollar amount $28) then they gave the pizza guy a $2 tip bringing the total to $30.  The three guys didn't get $3 back they got $5 which means they didn't pay $9 each for the pizza, they payed $9 and some obscure amount of cents, and since 5 isn't divisible by 3 they gave the pizza guy a $2 tip so each of them would get $1 instead of a having to do all this damn math we're doing to figure out this fucking problem.

Quantum theory, obviously.

 It sounds a lot like this riddle I know...

A wealthy Arab owned a stable of seventeen horses. When he died he bequeathed the horses to his three sons. The will stated that eldest son was to be given one half of the horses, the middle son was to be given one third of the horses, and the youngest son was to be given one ninth of the horses. The sons were distraught. It was clear to all that the horses could not divided in this way without making a bloody mess. 

  
The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.
its (0 + 30 = 30) for the pizza guy (30 - 30 = 0) for the guys
 
 
 The delivery guy goes back to the 3 guys and returns the 5 dollars.
then (30 - 5 = 25) for the pizza guy and (0 + 5 = 5) for the guys
  

 The 3 guys give the delivery guy a 2 dollar tip
then (25 + 2  = 27) for the pizza guy and (5 - 2 = 3) for the guys 
 
soo...the cost of the pizza now is 27$ and they have their 3 dollars left in their account.
 
A = L + OE people
 
if your still not getting it then you should think about it as 3 separate accounts for the guys instead of one single account

Oh man, I want some pizza now.

" 3 guys ended up giving a $2 tip, right? One of those guys paid $1 less than the rest. Not sure which one tho.  it's $10 + $10 + $9, not $9 + $9 + $9... that tip didn't magically come from nowhere. ;)  "

"   
The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.
its (0 + 30 = 30) for the pizza guy (30 - 30 = 0) for the guys
 
 
 The delivery guy goes back to the 3 guys and returns the 5 dollars.
then (30 - 5 = 25) for the pizza guy and (0 + 5 = 5) for the guys
  

 The 3 guys give the delivery guy a 2 dollar tip then (25 + 2  = 27) for the pizza guy and (5 - 2 = 3) for the guys   soo...the cost of the pizza now is 27$ and they have their 3 dollars left in their account. A = L + OE people  if your still not getting it then you should think about it as 3 separate accounts for the guys instead of one single account "

"   
The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.
its (0 + 30 = 30) for the pizza guy (30 - 30 = 0) for the guys
 
 
 The delivery guy goes back to the 3 guys and returns the 5 dollars.
then (30 - 5 = 25) for the pizza guy and (0 + 5 = 5) for the guys
  

 The 3 guys give the delivery guy a 2 dollar tip then (25 + 2  = 27) for the pizza guy and (5 - 2 = 3) for the guys   soo...the cost of the pizza now is 27$ and they have their 3 dollars left in their account. A = L + OE people  if your still not getting it then you should think about it as 3 separate accounts for the guys instead of one single account "

 
11 men wants separate rooms in a hotel but there are only 10 rooms available. The clerk says he can handle it and proceeded to assign the men to the rooms. How does he do it?

He puts 2 men in the 1st room, then he puts the third man in the 2nd room, the fourth man in the 3rd room, the fifth man in the 4th room and so on until he puts the tenth man in room number 9. He now take one of the two men out of the 1st room and placed him in the last, the 10th room. So he managed to put 11 men in 10 rooms with each one having a separate room?     

And this is why I have dropped Math each semester my advisor snuck it into my schedule!

"
Here is another one for you: 

 
11 men wanted separate rooms in a hotel but there were only 10 rooms available. The clerk says he can handle it and proceeded to assign the men to the rooms. How does he do it?

He puts 2 men in the 1st room, then he puts the third man in the 2nd room, the fourth man in the 3rd room, the fifth man in the 4th room and so on until he puts the tenth man in room number 9. He now take one of the two men out of the 1st room and placed him in the last, the 10th room. So he managed to put 11 men in 10 rooms with each one having a separate room?     

"

"
Here is another one for you: 

 
11 men wants separate rooms in a hotel but there are only 10 rooms available. The clerk says he can handle it and proceeded to assign the men to the rooms. How does he do it?

He puts 2 men in the 1st room, then he puts the third man in the 2nd room, the fourth man in the 3rd room, the fifth man in the 4th room and so on until he puts the tenth man in room number 9. He now take one of the two men out of the 1st room and placed him in the last, the 10th room. So he managed to put 11 men in 10 rooms with each one having a separate room?     

" 

This is one of the oldest and easiest riddles. I say riddles, because it was originally presented to me as a riddle.

you should subtract 2 from 27, not add it.  Why would you add there?

Mis-read as meth problem.

"  I'm really stumped here everyone... I everyone I talk to has no idea about this either, is they're something we're missing? 
 
 3 Guys order a pizza.   

The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.

$10 + $10 + $10 = 30

When the delivery guy goes back to the pizzaria, his boss says that he over charged them for the pizza, and to give them 5 dollars back (In loonies, or dollar bills depending on where you're from).

The delivery guy goes back to the 3 guys and returns the 5 dollars.

$30 - $5 = 25

The 3 guys give the delivery guy a 2 dollar tip and they each take 1 dollar back.

$1 + $1 + $1 + $2 = $5

This means that they only spent 9 dollars on the pizza each, instead of 10.

$9 + $9 + $9 = $27

Plus the 2 dollars they gave as a tip.
 
YOU DID IT WRONG HERE.  YOU DOUBLE COUNT THE TIP AND MISS THE 3 BUCKS THEY GOT BACK.

$27 + $2 = 29

Where did the other dollar go? 
"

"  I'm really stumped here everyone... I everyone I talk to has no idea about this either, is they're something we're missing? 
 
 3 Guys order a pizza.   

The pizza costs 30 dollars, so they give the delivery guy 10 dollars each.

$10 + $10 + $10 = 30

When the delivery guy goes back to the pizzaria, his boss says that he over charged them for the pizza, and to give them 5 dollars back (In loonies, or dollar bills depending on where you're from).

The delivery guy goes back to the 3 guys and returns the 5 dollars.

$30 - $5 = 25

The 3 guys give the delivery guy a 2 dollar tip and they each take 1 dollar back.

$1 + $1 + $1 + $2 = $5

This means that they only spent 9 dollars on the pizza each, instead of 10.

$9 + $9 + $9 = $27

Plus the 2 dollars they gave as a tip.

$27 + $2 = 29   <-----  this line is wrong

Where did the other dollar go? 
"

"
Here is another one for you: 

 
11 men wants separate rooms in a hotel but there are only 10 rooms available. The clerk says he can handle it and proceeded to assign the men to the rooms. How does he do it?

He puts 2 men in the 1st room, then he puts the third man in the 2nd room, the fourth man in the 3rd room, the fifth man in the 4th room and so on until he puts the tenth man in room number 9. He now take one of the two men out of the 1st room and placed him in the last, the 10th room. So he managed to put 11 men in 10 rooms with each one having a separate room?     

"

numbers are silly

"they didn't actually pay $9 each, the pizza was $25 and they each got back a dollar (making the dollar amount $28) then they gave the pizza guy a $2 tip bringing the total to $30.  The three guys didn't get $3 back they got $5 which means they didn't pay $9 each for the pizza, they payed $9 and some obscure amount of cents, and since 5 isn't divisible by 3 they gave the pizza guy a $2 tip so each of them would get $1 instead of a having to do all this damn math we're doing to figure out this fucking problem. "

Damn I hate math 

"numbers are silly "

The real question is, why did they only tip the guy after he went back to the pizza place and then return saying they were overcharged?

"The real question is, why did they only tip the guy after he went back to the pizza place and then return saying they were overcharged? "