There has never been a missing dollar. The situation says that each woman paid $10 for a bill of $30. The cashier then reveals that the actual bill is $25, and gives the waiter five $1 bills to return to the women. The waiter keeps $2 and returns to each woman a $1 bill.
So now the bill is $25. Since each woman was given back $1, they each ended up paying $9, for a total of $27. From this total, the waiter took $2 for himself, bringing the total down to the $25.
Each woman originally paid $10 for a total of $30. They were later given back each $1 in return, bringing the total to $27. With this new total, the women each had to have paid $9. However, the actual bill is still $25, meaning that they have still overpaid. To solve the problem, the waiter takes $2 for himself, causing the total down to the bill’s amount.
“Now, each of the ladies paid $9. Three times 9 is $27. The waiter has $2 in his pocket. Two plus 27 is $29. The ladies originally handed over $30.” It is the wording of these sentences that confuses readers. With each woman being given back $1, each woman has now paid $9, meaning that the adjusted total is now $27 (something these sentences do not specify). The $2 from the waiter’s pocket is from the $27, and therefore cannot be added to that total. The new adjusted total after the waiter’s removal is $25, which is exactly what the bill needed.
Here is math to illustrate my point one final time:
$10 + $10 + $10 = $30 (original bill)
$25 (real bill)
$30 – $5 = $25
$5= $1+ $1+ $1+ $1+ $1
Woman 1: $1 Woman 2: $1 Woman 3: $1
$10 – $1= $9
$9 + $9+ $9= $27 (adjusted total) $30- $1 – $1 –$1 =$27
Waiter: $1 + $1
$27 – $1 – $1 = $25
The restaurant has $25 which is what the real bill required ($25).
Basically, there is no missing dollar.
Rowan Counterintuitive 