What is the missing number: 60, 56, 48, _, 20

Question

This is a very hard problem

Answer 1

Let's look at the changes between each of the numbers.

60 - 56 = 4

56 - 48 = 8

48 - _ = ?

_ - 20 = ?

So we have a sequence:

4, 8, ?, ?

Let's start with something simple.  Continue that sequence like this:

4, 8, 12, 16

Now try that with the original numbers:

60 - 56 = 4 (good)

56 - 8 = 48 (good)

48 - 12 = 36 (maybe)

36 - 16 = 20 (good)

So the sequence subtracting 4, then 8, then 12, then 16, and so on works.

The missing number should be 36.