Multiple choice

The average age of 30 students is 15 years. It was observed that while calculating the average age, the age of a student was taken as 15 years instead of 9 years. What will be the correct average age?

  1. 14.2 years

  2. 16.4 years

  3. 15.6 years

  4. 14.8 years
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The sum of ages was 30 * 15 = 450. The error was adding 15 instead of 9, an excess of 6. The correct sum is 450 - 6 = 444. The correct average is 444 / 30 = 14.8.

AI explanation

The incorrect total age calculated for the 30 students was 15 multiplied by 30, which equals 450 years. The correct age of the student is 9 years instead of 15, so the total must be reduced by 6 years, making the correct total age 444 years. Dividing this correct total by the 30 students gives a correct average age of 14.8 years.

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