Multiple choice

The average age of 150 people watching a movie in a theatre is 23.7 years. If the age of 2 persons has been mistakenly written as 72 and 43 instead of 27 and 33, then what is the actual average age of the group of people?

  1. 23.22 years

  2. 23.33 years

  3. 24.15 years

  4. 24.45 years

  5. 24.76 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total sum of ages is 150 * 23.7 = 3555. The error was adding 72 and 43 (115) instead of 27 and 33 (60), meaning the sum was overstated by 55. The corrected sum is 3555 - 55 = 3500, and the new average is 3500 / 150 = 23.33.

AI explanation

The total age difference to be corrected is (27 + 33) - (72 + 43) = 60 - 115 = -55 years. Using the average correction formula, the change in the average is -55 / 150 = -0.366 years. Subtracting this from the incorrect average gives 23.7 - 0.367 = 23.33 years.

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