Multiple choice

Consider the following table in respect of students of 4 schools who appeared in a test: School Number of students Average marks in the test I 60 60 II 50 80 III 50 40 IV x 50 If the average marks of the students of all four schools are 58, then how many students appeared from School-IV?

  1. 38

  2. 40

  3. 42

  4. 44
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total students = 60 + 50 + 50 + x = 160 + x. Total marks = (60*60) + (50*80) + (50*40) + (x*50) = 3600 + 4000 + 2000 + 50x = 9600 + 50x. Average = (9600 + 50x) / (160 + x) = 58. 9600 + 50x = 9280 + 58x. 320 = 8x, so x = 40.

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