Multiple choice

The average of 6 numbers is 18. If one number is excluded, the average becomes 17. What is the excluded number?

  1. 22

  2. 23

  3. 21

  4. 20
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B Correct answer
Explanation

Sum of 6 numbers = 6 * 18 = 108. Sum of 5 numbers = 5 * 17 = 85. Excluded number = 108 - 85 = 23.

AI explanation

Using the excluded number formula, Excluded Number = (Original Average x Original Count) - (New Average x New Count). The sum of all 6 numbers is 6 x 18 = 108. The sum of the remaining 5 numbers is 5 x 17 = 85. The excluded number is 108 - 85 = 23.

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