Brain Dare have posted this mathematical brain teaser on their Facebook page and it’s been causing quite the rift in the comments section. The puzzle doesn’t give much away, but to obtain the solution to the fourth equation, you must uncover the method used to answer the previous three equations. Essentially, you have to find the hidden algorithm.
Given the chance, people can argue about anything on the Internet. But this puzzle does appear to have two separate solutions. Brain Dare, however, says only one is correct.
What do you think the missing number is? Scroll down to find out.
According to Brain Dare, the solution is 96. Here’s how they worked it out.
Their solution involves introducing multiplication into the mix. First, you multiply the first number by the second number. Then, you simply add the product of those two numbers to the first number. Like so:
1 + (1 x 4) = 5
2 + (2 x 5) = 12
3 + (3 x 6) = 21
8 + (8 x 11) = 96
However, if you did manage to work out a solution for the sum yourself, there’s a fair chance you came to the answer 40 instead. Here's how you come to that answer:
1 + 4 = 5
2 + 5 + 5 = 12
3 + 6 + 12 = 21
8 + 11 + 21 = 40
Of course, there’s no right or wrong answer, even if there is an “official” correct solution.