Three friends decide to go out for dinner. They order a meal that costs $30. They each contribute $10, giving a total of $30 to the waiter. After finishing their meal, the waiter realizes that there was a special promotion and the meal only cost $25.
To rectify this, he takes $5 from the cash register to return to the friends. However, he thinks about how he wants to keep $2 for himself and gives the friends back only $3.
Now, each friend has paid $10, but they received $1 back each, meaning they effectively paid $9 each for the meal. So, $9 multiplied by 3 friends equals $27. Add the $2 that the waiter kept for himself, and you get $29.
What happened to the missing dollar?
By Elish