Multiple choice

Two high school classes took the same test. One class of $20$ students made an average grade of $80$%; the other class of $30$ students made an average grade of $70$%. The average grade for all students in both classes is

  1. $75$%
  2. $74$%
  3. $72$%
  4. $77$%

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The weighted average is ((20 * 80) + (30 * 70)) / (20 + 30) = (1600 + 2100) / 50 = 3700 / 50 = 74%.

AI explanation

The total sum of the grades for the first class is 20 times 80, which is 1600. The total sum for the second class is 30 times 70, which is 2100. Combining these gives a total of 3700 for all 50 students, so dividing 3700 by 50 yields an overall average grade of 74 percent.

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