Multiple choice

Find the missing number in the place of question mark (?) in the series given below. $17, 9, ?, 16.5, 35, 90$

  1. 5

  2. 15

  3. 10

  4. 20

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is: multiply by increasing factor (0.5, 1, 1.5, 2, 2.5) and add the same factor. 17×0.5+0.5=9, 9×1+1=10, 10×1.5+1.5=16.5, 16.5×2+2=35, 35×2.5+2.5=90. The missing number is 10.

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