1, 1, 2, 3, 4, 5, 8, 13, 21 - which one doesn't belong to this series?
Fibonacci Sequence is a sequence in which each term is the sum of the previous two terms. These were invented to keep the sound of pair of rabbits born each year.
Answer: In the given sequence, 4 doesn't belong to the series.
Let's understand the solution in detail.
From the given numbers in the sequence, we can very well predict that it must be a Fibonacci series.
As we know, in Fibonacci sequences, a term is equal to the sum of the previous two terms.
If the first number is given by f0, and the second number by f1, then the third number is given by f2 = f0 + f1.
Hence, from the given series, we see that:
⇒ 1 + 1 = 2
⇒ 1 + 2 = 3
⇒ 2 + 3 = 5
⇒ 3 + 5 = 8
⇒ 5 + 8 = 13
⇒ 8 + 13 = 21
From the above calculations, we see that 4 doesn't fit in the series.