Find the missing term in the series below: 2, 5, 9, 19, 37, ?, ........
2022
Find the missing term in the series below:
2, 5, 9, 19, 37, ?, ........
Answer: B. 75 — ConceptIn a number series, first test a consistent operation or a short repeating cycle of operations between consecutive terms. For an alternating cycle,…
- A.
74
- B.
75
- C.
71
- D.
72
Attempted by 4 students.
Show answer & explanation
Correct answer: B
Concept
In a number series, first test a consistent operation or a short repeating cycle of operations between consecutive terms.
For an alternating cycle, apply the operations in their fixed order and repeat the cycle to generate the next term.
Application
From 2 to 5: 2 × 2 + 1 = 5.
From 5 to 9: 5 × 2 − 1 = 9.
From 9 to 19: 9 × 2 + 1 = 19.
From 19 to 37: 19 × 2 − 1 = 37.
The cycle now returns to ×2+1, so 37 × 2 + 1 = 75.
Cross-check
The signs of the adjustment are +1, −1, +1, −1, +1 while every term is first doubled. This reproduces every given transition and yields 75.