Multiple choice

The strength of three classes is in the ratio 5 : 6 : 7. If 20% students in class A, 25% students in class B and 40% students in class C are below average, what % of students in the three classes is below average?

  1. 29.44%

  2. 30%

  3. 24%

  4. 13%

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

Let students be 5x, 6x, 7x. Total = 18x. Below average: 0.2(5x) + 0.25(6x) + 0.4(7x) = 1x + 1.5x + 2.8x = 5.3x. Percentage = (5.3x / 18x) * 100 = 29.44%.

AI explanation

Assume the total number of students across the three classes is the sum of the ratio parts, which is 5 plus 6 plus 7 equals 18. The number of below average students is 20 percent of 5, 25 percent of 6, and 40 percent of 7, totaling 1 plus 1.5 plus 2.8 equals 5.3. Dividing 5.3 by 18 gives the overall percentage of below average students, which is approximately 29.44 percent.

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