Choose the number that will come next in the following series.
1, 2, 5, 10, 13, 26, ?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 29
The steps are not all of one kind, so test two operations in turn: ×2 and +3 alternately.
\(1\times2=2\), \(2+3=5\)
\(5\times2=10\), \(10+3=13\)
\(13\times2=26\)
The next step is +3: \(26+3=29\)
So the next number is 29.