Question

Sequence. 4, 13, 28, 49, ?

Answer 1

Sequence: 4, 13, 28, 49
Now, differences between numbers = 13-4, 28-13, 49-18
= 9, 15, 21
We can see, difference is increasing by 6 at each step, so it would be 27 for next.

Next number = 49 + 27 = 76

In short, Your Answer would be 76

Hope this helps!

Answer 2

You have to list the differnences, then the 2nd differences

4, 13, 28, 49, ?
  9   15  21
      6   6    6
answer: 76