Multiple choice

Directions: Find the missing term in the given series. 445, 221, 109, 53, 25, 11, ?

  1. 2

  2. 3

  3. 4

  4. 5

  5. 9
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is (x - 3) / 2 = next term. 445 -> 221 (445-3)/2 = 221. 221 -> 109 (221-3)/2 = 109. 109 -> 53 (109-3)/2 = 53. 53 -> 25 (53-3)/2 = 25. 25 -> 11 (25-3)/2 = 11. 11 -> (11-3)/2 = 4.

AI explanation

The pattern in this series is that each number is multiplied by 2 and then 3 is subtracted to obtain the next number. For example, 445 * 2 - 3 = 887, but the given second term is 221, indicating a different rule. Working backwards, adding 3 to a term and dividing by 2 gives the previous term; (445 + 3) / 2 = 224, which does not match. The correct rule is subtracting 3 and dividing by 2: (445 - 3) / 2 = 221, (221 - 3) / 2 = 109, (109 - 3) / 2 = 53, (53 - 3) / 2 = 25, and (25 - 3) / 2 = 11. Applying this logic to the last term gives (11 - 3) / 2 = 4.

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