It’s Follow-Up Friday: Math Puzzle Madness edition!

Welcome to Follow-Up Friday!

By this time, you know the drill. Follow-Up Friday is a chance for us to revisit the subjects of previous posts and bring the PuzzleNation audience up to speed on all things puzzly.

And today, I’d like to revisit the world of viral puzzles and discuss two that have been making the rounds on Facebook recently.

If you’ve been on social media recently, you’ve no doubt seen one or both of these puzzles:

math

14962617_1223950097651735_5609824945112529117_n

Each was probably accompanied by some hyperbolic phrasing like “95% of people and most dogs can’t solve this puzzle! Heck, they can’t even agree on an answer! CAN YOU?!?!?!?!”

Well, duh. Of course they can’t agree on an answer. There’s plenty of room to make different assumptions.

Let’s look at the first puzzle again.

math

Now, if you take the puzzle at face value, the chain would appear to be this:

1 + 4 = 5

2 + 5 (+5) = 12 (We’ve added the previous answer, which is where the +5 comes from.

3 + 6 (+12) = 21

8 + 11 (+21) = 40

So the answer is 40.

But wait. if you assume that the pattern continues for the digits between 3 and 8, you end up with this:

1 + 4 = 5

2 + 5 (+5) = 12

3 + 6 (+12) = 21

4 + 7 (+21) = 32

5 + 8 (+32) = 45

6 + 9 (+45) = 60

7 + 10 (+60) = 77

8 + 11 (+77) = 96

And, in truth, it could be either. You’re not given enough information to know for sure how to proceed. It’s a coin toss whether the last line immediately follows the third line, or whether there’s a whole bunch of lines in between and you need to “get the pattern” to extrapolate the 8th line.

Now let’s look at that second puzzle again.

14962617_1223950097651735_5609824945112529117_n

This one also has the potential for alternate answers, but instead of inferences, it depends on whether you follow the traditional order of operations (parentheses, exponents, multiplication/division, addition/subtraction) or you simply read left to right.

If you use traditional order of operations, you end up with:

Horse + Horse + Horse = 30, so Horse = 10.

Horse + Horseshoes + Horseshoes = 18, so Horseshoes = 4 and Horseshoe = 2.

Horseshoes – Boots = 2, so Boots = 2 and Boot = 1.

Boot + Horse x Horseshoe = Boot + (Horse x Horseshoe) = 1 + (10 x 2) = 21.

But if you simply read the last equation from left to right, you end up with:

Boot + Horse x Horseshoe = 1 + 10 x 2 = 11 x 2 = 22.

So, in fairness, there is no right answer to either puzzle, given the information we have.

Which, to me, doesn’t seem like a great puzzle, but it probably makes for great clickbait.


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