School-Safe Puzzle Games

## Math Puzzle- 3 Men in Restaurant

Three men entered a restaurant for lunch. When they went  to the counter to pay, the owner placed a box down in front of them, and ordered the 1st man to put all the money in his pocket into the box, and take 2 dollars out for the bus.

The owner then told the 2nd man to put in as much as what was now left in the box, and take 2 dollars for the bus.

Finally, the owner told the 3rd man to put in as much as what was now left in the box, and take 2 dollars for the bus.

He then went and looked in the box, and to his surprise, nothing was there!

Question: How much money did the 1st man put into the box?

Much Thanks to Falwan for submitting! Have a puzzle by Suineg that will go up later this week!

### 28 Comments to “Math Puzzle- 3 Men in Restaurant”

1. brianu | Profile

six dollars

2. cheddarmelt | Profile

The first man put in \$3.50 and took \$2, leaving \$1.50.
The second man matched the \$1.50, making \$3, and took \$2, leaving \$1.
The third man matched the \$1, making \$2, and took the \$2.

3. TonyTKL | Profile

The first person placed 1.5 in the box.

4. joe | Profile

the original man put 3.50 in.

1st man: puts in 3.50 and takes out 2 = 1.50 left
2nd man: puts 1.50 in and takes 2 out (1.50+1.50-2) = 1 left in box
3rd man : puts 1 in and then takes 2 (1+1-2) = nothing left in box.

5. Roel | Profile

* Suppose x is the money the first man put in.
* So when he finished paying there was x-2 in the box.
* Then the second man doubled that amount: 2.(x-2) and took two out: 2.(x-2)-2.
* Again the third man doubled that amount: 2.(2.(x-2)-2) and took two out: 2.(2.(x-2)-2)-2.

And this should be 0. Solving this equation:
* 2.(2.(x-2)-2)-2 = 0
* 2.(x-2)-2 = 1
* x-2 = 3/2
* x = 7/2 = 3.5

So the first man put in 3.5 dollars.

6. Mashplum | PUZZLE MASTER | Profile

Well, it was about that time I begin to get suspicious. I said, “Chef, my boy, why do you need tree-fitty?”

He said, “My imaginary friend Boo-Boo the dinosaur wants it.”

So I went to my son’s room, and sure enough, there was that damn Loch Ness Monster!

7. Bobo The Bear | PUZZLE MASTER | Profile

What a strange restaurant. I wonder how they split tips.

The first man put in \$3.50, took \$2.00, and left \$1.50 in the box.
The second man doubled it to \$3.00, took \$2.00, and left \$1.00 in the box.
The third man doublet it to \$2.00, took \$2.00, and left the box empty.

8. suineg | PUZZLE MASTER | Profile

Cool puzzle, I think it could be solved backwards like this:
0(2\$ taken for bus by man 3)-> 2(1\$ put by man 3)-> 1 (2\$ taken for bus by man 2)-> 3(1.5\$ put by man 2)-> 1.5 (2\$ taken by man 1 for the bus)-> 3.5 (3.5\$ in the pocket of man 1)
So the answer will be 3.5\$, cool.

9. fuzzy | Profile

The first man put in \$3.50, and took \$2.
The second man put in \$1.50, and took \$2.
The last man put in \$1 and took \$2.

10. Shawn | PUZZLE GRANDMASTER | Profile

\$3.50

First man puts in X-2
Second man puts in [(X-2)-2]
Third man puts in (X-2)+[(X-2)-2]-2
[(X-2)] + [(X-2)-2] + {[(X-2)+(X-2)-2]-2} = 0
X=3.5

11. BlindCupid | Profile

3.50.
The first man puts 3.50 in the box, and takes out 2 dollars
Box:=3.50-2.00
=1.50
The second man puts the same amount as what’s in the box (1.50) and takes out 2 dollars
Box:=1.50+1.50-2.00
=3.00-2.00
=1.00
The third man puts the same amount as whats in the box (1.00) and takes out 2 dollars
Box:=1.00+1.00-2.00
=2.00-2.00
=0.00
The box has nothing left. The first man put 3.50 dollars.

12. brianu | Profile

forget what I said, I believe it is 3.50.

13. Blusummers13 | Profile

\$3.50
[(x-2)*2-2]*2-2=0
x=3.5

14. Obiwan | Profile

First man put in \$3.50.

15. Kllr Wolf | Profile

Unless my brain is really too tired to be thinking (which I actually suspect is true), the first man put \$3.50 in the box.

(p1-2) = x
x + (x-2) = y
y + (y-2) = 0

Solve and you get p1 = £3.50

17. Hex | PUZZLE MASTER | Profile

\$3.5

18. michaelc | Profile

The owner should have had them washing dishes!

The 3rd man must have put one dollar in, as he took 2 and that left 0 in the box.
The 2nd man must have put 1.50 in as he took 2 and that left 1 box.
The 1st man must have put 3.50 in as he took 2 and that left 1.50 box.

An equation form, let x equal amount put in by man 1.

(X-2)= money in box after man 1
(X-2)+(X-2) -2 = money in box after man 2
{(X-2) + (X-2) – 2} + {(X-2) + (X-2) – 2} -2 = 0 after man 3
4x=14
x=3.50

19. APEX.JP | Profile

Solved working backwards adding to the box
Man #3: \$2/2 = \$1
Man #2: \$(2+1)/2 = \$1.50
Man #1: \$2+1.50 = \$3.50

20. Yar | Profile

Depends on whether or not there was any money already in the box when the owner set it in front of them. But similar to what many have said, after the first man put all of his money into the box, his money plus any money already in there would equal tree fiddy (\$3.50) in the box. You work the events backwards to figure this out. ((0 + 2) / 2 + 2) / 2 + 2 = 3.5

21. infinityaurora314 | Profile

\$3.50

22. tcxman | Profile

ans: \$3.50

23. deepside0058 | Profile

working backwards, we will get 3 dollars and 50 cents!!!!