Question

sum of the average marks of2 students in an examination is 90,if the average marks of one student is double the average marks of the anther .then find the average marks of each student individually using cramer's rule​

Answer 1

Explanation:

100

Let the number of the passed candidates=x.

Then the number of the failed candidates=120-x.

Now the total of the marks obtained by 120 candidates=120×35=4200.

The total of the marks obtained by passed candidates=39×x=39x. and

the total of the marks obtained by failed candidates=(120−x)×15=4200.

Then the total=39x+(120−x)×15=4200

⟹24x=4200−1800

⟹x=100

So the number of passed candidates=100.

Ans- Option A.