 So, this McDonalds brain teaser has kept thousands of you guessing over the last few days!

Did you get it right? #### 15.

Bearing in mind that the rule of multiplication is you always multiply first (BODMAS)…

So,

1 drink =10

1 burger = 5

Only 1 fries = 1

– yes?

Therefore…

10×1=10, + 5 = 15

Let me know if you are one of the ‘geniuses’!

Source:The Telegraph

1. Richard Weatherwax says:

In mathematics XX = X^2. Not 2X.

In line 3, we agree that the burger = 5.
Subtracting 5 from each side of the equation in line 3 gives us:

(fries)(fries) + (fries)(fries) = 4.

That can be expressed as:

2(fries)(fries) = 4.

Now divide each side by 2, and you have:

(fries)(fries) = 2.

In mathematics, XX = Xsquard. Not 2X. Therefore we have:

(fries)^2 = 2.

Taking the square root of each side we have:

fries = square root of 2.

Line 4 now becomes:

5 + (square root of 2)10

Which is an irrational number, and cannot be expressed in decimals.

2. Ken James says:

You’re using a rule no one uses and hasn’t for years. I work with complex accounting problems every day and have never encountered equations written this way; neither do I write them this way. The use of parenthesis separates the various functions. I took algebra in the late 50’s and don’t recall being taught this obscure rule. It was obviously used before someone brighter decided to use parenthesis.

3. Shirley says:

This must be some kind of new math – not the way I was taught to do math 50 years ago – my answer is 60 – same as KK comment. 🙂

4. Maryanne says:

Answer is 25. Fries = 2 each not 1.

5. Zoenoodles says:

• Zoenoodles says:

OOPS – I was wrong!!! It is 15 – Mea Culpa!

6. Judith Bell says:

I got 15.
Each shake = 10 so 10 x 3 = 30
Each burger = 5 so 10 +5 +5 = 20
Each fry = 2 so 5 +2 +2 = 9
Last equation: 1 fry x 10 = 10 + 1 burger, 5 = 15

• Firstoneout says:

But each fry is worth 2, not one so 2×10=20, +5 = 25.

• John says:

There are 4 fries in line 3.

Four fry boxes = 4, so one fry box = 1

7. Dana Duncan says:

In the equation they are showing 4 fries in total, making the value of the fries 1 each.
(burger) 5 + (fry) 1 x (shake) 10 = 60 (no parentheses were used to change the order of the problem so this math problem should have been straight across add, multiply then state the answer.
BODAS rule means:
Brackets, Orders (powers and roots), Division and Multiplication, … When all your operations are the same level (for example, all division or multiplication), simply work from left to right.

8. KK says:

Drink 10
Burger 5
Fries 1 ea.
1 burger + 1 Fry = 6 x 1 Drink = 60

• Firstoneout says:

9. Eileen says:

No, the answer is 16, not 15

10+10+10=30
10+5+5=20
5+2+2=9
5+1*+10=16

*two fries for \$2.00 means 1 fries for \$1.00

• Donna Ashworth says:

You must always multiply first Eileen, (BODAS rule) so I think that’s what is confusing so many of us.. I didn’t get it right!

10. Fries = 1? I think not.
Burger 5 + 2 fries = 9 so fries are 2 surely?

• Kayla says:

The graphic shows 4 pictures of fries plus 1 burger equals nine.(each picture of fries equals 1)

One burger (5)+ 1 picture of fries(1)x 1 drink(10) = 15

• A Guest says:

d=drink
b=burger
f=fry

d+d+d=30
3d=30
d=30/3
d=10

d+b+b=20
10+2b=20
2b=10
b=10/2
b=5

b+2f+2f=9
5+2f+2f=9
4f=4
f=1

b+f*d=x
5+1*10=x
5+10=x(order of operations multiply before add)
15=x

• Donna Ashworth says:

There are 2 packs of fries which equal 2, so I pack is only 1… 😄

• Michelle says:

I know there’s only 1 fries but doesn’t that count as 2 Because burger is 5, to get to 9, it’s 4. But there IS only 1. So surely it’s 2. Which makes the answer 25. Surely

• KK says:

Drink = 10
Burger = 5
Fries = 1

5+1= 6 x 10 = 60

• patsy says:

Why is the fry only worth 1 when it is worth 2 on the previous problem?

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