Find the missing term in the following series.
12, 21, 39, 75, ?, 291
Show answer & explanation
Correct answer: A
Explanation
The pattern followed in the given series is:
• 12 + 9 = 21 (or 12 × 2 − 3 = 21)
• 21 + 18 = 39 (or 21 × 2 − 3 = 39)
• 39 + 36 = 75 (or 39 × 2 − 3 = 75)
• 75 + 72 = 147 (or 75 × 2 − 3 = 147)
• 147 + 144 = 291 (or 147 × 2 − 3 = 291)
Each successive difference is doubled (9, 18, 36, 72, 144).
Therefore, the missing term is 147.