what is the next number in the sequence 1, 1, 2, 3, 5, 8, 13, ...
A)17
B) 20
C) 21
D) 24

Question

what is the next number in the sequence 1, 1, 2, 3, 5, 8, 13, ... 
A)17
B) 20 
C) 21
D) 24

anonymous · Answer

how is the third term related to the first and second?

anonymous · Answer

Hint: this is the famous Fibonacci sequence

cwrw238 · Answer

this is the fibonacci series

anonymous · Answer

How is the fourth term related to the second and third?

cwrw238 · Answer

think sum

anonymous · Answer

Allie, what have you tried?

anonymous · Answer

No, not 20.  That's a guess.

anonymous · Answer

Listen to Tonks, he's putting you on the right track.

anonymous · Answer

21

anonymous · Answer

Tonks is telling you to find a pattern between any 3 successive numbers.  That will lead you to the right answer without just giving you a number.  You will then see the underlying basis for this very famous sequence.  Give Tonks some credit.