A graphic shows a series of odd math equations and asks readers to fill in the final answer. How would you solve this equation and what answer do you think is best?

First, let’s take a look at what we are seeing. (See the image below)

The image below contains the following math problem, often with a caption that reads:

*We can’t figure this out… Can you? 92% of people fail it. Good luck!*

1+5 = 12

2+10 = 24

3+15 = 36

5+25 = ?

After considerable debate here, we’ve come to the conclusion that there are three plausible theories on how to solve this, resulting in two different answers – depending on how you look at it.

*Update: We would like to point you to the comment by DrDave, who appears understand this puzzle far better than anyone at Wafflesatnoon.com! We’re presenting a dumbed-down version of his method as Answer #4*

**Answer 1 – Pattern Theory
**If we look at this as a pattern, and not 4 separate math problems, then the answer to “5+25=” should be

*. If this is a pattern, then one row of the pattern was omitted. Consider looking at the problem this way:*

**60**1 |
5 |
12 |

2 |
10 |
24 |

3 |
15 |
36 |

4 |
20 |
48 |

5 |
25 |
60 |

If we view the equation in the manner above, then “4+20 = 48″ was omitted from the original problem for reasons unknown. As you can see, however, the pattern theory holds that each *column* is its own pattern. The first column increases by 1, the second column increases by 5, and the third column increases by 12.

**Answer 2 – Days and Weeks as Units**

Another theory also yields an answer of * 60*. This theory holds that the first two columns equal units of weeks and days respectively, and the third column represents days. Thus:

1 week + 5 days = 12 days

2 weeks + 10 days = 24 days

3 weeks + 15 days = 36 days

5 weeks + 25 days = 60 days

**Answer 3 – Trick Question**

If we look at the problem literally, then the answer to “5+25″should be * 30*. The logic here is that 3 incorrect answers in a row should not affect the answer to the problem posed to readers. Thus, 5+25 should be 30.

**Answer 4 – Dr Dave’s Fibonacci series**

As commenter DrDave points out below, this problem is a “Fibonacci series.” And yes, we had to look that up, too. Even though he, too, comes up with 60 as an answer, his method is different than anything we’ve seen yet. Though his explanation is in much more detail, perhaps the easiest way to look at it is to ignore the + and =, and just add the numbers in two columns to determine the next value. Thus:

1 5 12

+2 +10 +24

—————–

3 15 36

Then:

2 10 24

+3 +15 + 36

——————

5 25 60

**Readers**

The overwhelming opinion of commenters on our Facebook page is that the answer should be 60, though the ways of achieving this vary greatly.

**Your Turn**

What solution do you feel is the best to solve this problem? Do you have another theory that we didn’t pose here? Let us hear from you in the comments below.

*Article updated April 7, 2013*

Pijod.bs

June 23, 2014 at 6:50 pm

So basically the Dr Dave’s Fibonacci series is based on 1^x+ 5^x=12^x ,because rest of the equation it`s depending from pattern of first equation in this case 1+5=12 ?

Pijod.bs

June 23, 2014 at 3:23 pm

hi, I have one more answer ,but I did not read all the coments below ,so maybe somewone alredy routh it .

1.) so here it is :

(1+1)+(5+5) = 12

(2+2)+(10+10) = 24

(3+3)+(15+15) = 36

(4+4)+(20+20) = 48

(5+5)+(25+25) = 60

(6+6)+(30+30) = 72

…and so on ….

or:

y*2+x*2 = Z

or:

z2=y+x > (z-x)-(y+x)=0 ,the x is important because only with x you can do the math ,otherwise you can not calculate the smallest number 0 zero

vijay darak

June 15, 2014 at 9:30 am

Now there are two approach

First is 5 + 25 is 11 + 55 = 66 as 5 is equal to 11.

2nd approach is replace 5 by y and y =11

Now y+ y*y

11 + 11*11= 132

2nd is equally logical

Milan Hoogan

June 3, 2014 at 6:08 am

132….How does this theory sound?? Don’t look at it like a pattern.. But just four different equations.. 60 does seem like an obvious answer, but I just wanted to see if there could be any other approach so I just solved for “5”: From the first equation we have the following.. 1+5=12 => 5=12-1 => 5=11… Hence the last equation is.. 5 + 25 => 5 + 5*5 => 11 + (11*11) = 132.. Let me know if you guys think it makes sense..

Jpe

April 25, 2014 at 6:27 am

My answer is similar to answer 4 except i added the omitted series of 4

1+5= 12

2+10= +24

———–

3+15= 36

4+20= 60 (added 24+36)

5+25= 96 (added 36+60)

Ryan

April 23, 2014 at 1:04 pm

1st numbers are all prime numbers hence no 4