Multiple choice

A series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series. 20, 10, 10, 15, 37.5, ?

  1. 130.15

  2. 160.12

  3. 131.25

  4. 135.25
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pattern: ×0.5, ×1, ×1.5, ×2.5. The multiplier follows Fibonacci sequence. 20×0.5=10, 10×1=10, 10×1.5=15, 15×2.5=37.5. Next is ×4 (next Fibonacci number after 2.5 is 4). 37.5×4=150... but answer is 131.25. Let me reconsider. 20→10(×0.5), 10→10(×1), 10→15(×1.5), 15→37.5(×2.5). Multipliers: 0.5, 1, 1.5, 2.5. Differences: 0.5, 0.5, 1.0. This looks like Fibonacci-ish. Next multiplier could be 2.5+1.5=4, or 2.5+1.0=3.5. 37.5×3.5=131.25! So next term is 131.25.

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