QUESTION 10 What will be the missing term of the series?
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QUESTION 10
What will be the missing term of the series?
9, 15, 24, 48, ___, 192, 384
Show answer & explanation
Answer: C. 96
The series follows a pattern of alternating operations: multiply by a factor, then add or apply a different rule. Analyzing: 9 → 15 (+6), 15 → 24 (+9), 24 → 48 (×2), 48 → 96 (×2), 96 → 192 (×2), 192 → 384 (×2). The pattern shows additions in the first two steps, then consistent doubling from 24 onwards. The missing term is 96.
Step-by-step Derivation:
Step 1: Identify transitions:
- 9 to 15: difference = +6
- 15 to 24: difference = +9
- 24 to 48: ratio = ×2
- 48 to ?: should be ×2 = 96
- 96 to 192: ratio = ×2
- 192 to 384: ratio = ×2
Step 2: From 24 onwards, each term is exactly double the previous term (geometric progression with ratio 2).
Step 3: Missing term = 48 × 2 = 96
Verification: 9, 15, 24, 48, 96, 192, 384
- 48 × 2 = 96 ✓
- 96 × 2 = 192 ✓
- 192 × 2 = 384 ✓