Multiple choice

In a certain test, a class with 20 students had an average score of 60 and a class with 25 students had an average score of 80. What was the average score of the 45 students (rounded to the nearest integer)?

  1. 70

  2. 71

  3. 72

  4. 75

  5. Cannot be determined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total score = (20 * 60) + (25 * 80) = 1200 + 2000 = 3200. Average = 3200 / 45 = 71.11. Rounded to the nearest integer, this is 71.

AI explanation

Calculate the total score of the first class by multiplying 20 students by their average of 60, which equals 1200. Calculate the total score of the second class by multiplying 25 students by their average of 80, which equals 2000. Using the weighted average formula, add these totals to get a combined score of 3200. Divide this combined score by the total number of students, which is 45. The result is 71.11, which rounds to 71.

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