Choose the number that will replace the question mark (?) in the following series.
5, 10, 8, 16, 14, 28, 26, 52, ?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 50
The steps are not all of one kind, so test two operations in turn: ×2 and −2 alternately.
\(5\times2=10\), \(10-2=8\)
\(8\times2=16\), \(16-2=14\)
\(14\times2=28\), \(28-2=26\)
\(26\times2=52\)
The next step is −2: \(52-2=50\)
So the missing number is 50.