Multiple choice

Find the wrong number in the following number series. 8, 17.5, 64.75, 157.375, 561.3125, 1400.78125

  1. 17.5

  2. 64.75

  3. 157.375

  4. 561.3125

  5. 1400.78125
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is: ×2+1.5, ×3.5+2.5, ×2.5-3, ×3.5+... This is complex. Let me check: 8×2+1.5=17.5, 17.5×3.5+2.5=63.75 (not 64.75). Alternative: 8×2+1.5=17.5, 17.5×3.7=64.75, 64.75×2.43=157.375. Pattern unclear. Checking 157.375: 157.375×3.5+...=561.3125. The multiplier varies. 157.375 seems to be the wrong number based on the pattern.

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