Question

what is the total strength of class, if average of 30 student of section A and 35 students of section B are 75%, average of remaining student are 65% and average of total student are 70%​

Answer 1

Answer:

Let n be the number of students who passed the exam.

Let m be the number of students who failed the exam.

Then n+m=75. Since the average mark was 35 the total mark was 75x35=2625. Therefore we also know :

55n+30m=2625

11n+6m=525 Since we know that m=75-n then ;

11n+6(75-n)=525

11n+450–6n=525

5n=75

n=15

m=75–15=60

The number of students who failed is 60.

The number of students who passed is 15.

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