Find the next number: 3, 4, 7, 11, 18, 29, ?

40Correct answerYour answer45Correct answerYour answer47Correct answerYour answer58Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer C

Correct answer: C

Differences 1, 3, 4, 7, 11 do not follow an obvious pattern, but notice $3 + 4 = 7$ , $4 + 7 = 11$ , $7 + 11 = 18$ , $11 + 18 = 29$ .
Each term is the sum of the two before it, so the next is $18 + 29 = 47$ .

Worth noting

40 adds the last difference (11) again, and 58 doubles 29. When the differences look like the series itself, test 'sum of the previous two'.

Ten questions from Number and Letter Series, at your own pace.

Ten questions from Number and Letter Series, at your own pace.

Explanation