Multiple choice

On a certain test, 3 students each had a score of 90, 9 students each had a score of 80, 4 students each had a score of 70, and 4 students each had a score of 60. What was the average (arithmetic mean) score for the 20 students ?

  1. 74.0

  2. 75.5

  3. 74.5

  4. 76.0

  5. 76.5
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B Correct answer
Explanation

Total sum = (3*90) + (9*80) + (4*70) + (4*60) = 270 + 720 + 280 + 240 = 1510. Average = 1510 / 20 = 75.5.

AI explanation

The total score for all 20 students is calculated by multiplying the number of students by each score and summing the results: (3 multiplied by 90) plus (9 multiplied by 80) plus (4 multiplied by 70) plus (4 multiplied by 60), which equals 1510. To find the arithmetic mean, divide this total score by the 20 students. The calculation 1510 divided by 20 results in an average score of 75.5.

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