Multiple choice

Average age of a class having 36 students is 16 years and 6 months. When certain number of new students entered in class having average age of 19 years 3 months, new average age of class becomes 17 years and 9 months. Find the total number of students who entered in class.

  1. 24

  2. 20

  3. 32

  4. 33

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

Let original students = 36, avg age = 16.5 years. Let x = new students, avg age = 19.25 years. New avg = 17.75 years. Total age equation: 36 x 16.5 + x x 19.25 = (36+x) x 17.75. 594 + 19.25x = 639 + 17.75x. 1.5x = 45. x = 30. Since 30 is not among options A-D (24, 20, 32, 33), answer is E (None of these).

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