What is the answer 5+[31/4+5]=

Question

How to show the work for problem 5+[31/4+5]=17.75

Answer 1

1 + 4 = 5

2 + 5 = 12

3 + 6 = 21

8 + 11 = ?

So - what's the answer to 8 + 11?

Randall's post has more than 1.1 million comments so far, and the vast majority of people are suggesting either 40 or 96 as the answer. So which of those is right - and why?

The solution

Well - either 40 or 96 could be the right answer, depending on how you look at it.

For 2 + 5 to equal 12, and 3 + 6 to equal 21, there's clearly something missing. Here are the two most commonly suggested solutions.

• For the answer to be 40: add the solution to the previous line to the numbers on the next line, EG:

1 + 4 = 5

5 + 2 + 5 = 12

12 + 3 + 6 = 21

21 + 8 + 11 = 40 

• For the answer to be 96: multiply the first number by the second number, then add the outcome to the first number, EG:

1 + (1 x 4) = 5

2 + (2 x 5) = 12

3 + (3 x 6) = 21

8 + (8 x 11) = 96

Answer 2

First of all we deal with [31/4+5]=[7.75+5]=[12.75]. There is nothing further to evaluate in the brackets so we just write 12.75 where the brackets were: 5+12.75=17.75.