Question

8. The average of marks obtained by 120
candidates was 35. If the average of marks of
passed candidates was 39 and that of failed
candidates was 15, the number of candidates
who passed the examination is​

Answer 1

Answer:

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.