Question

The average of marks obtained by 120 condidates was 35. If the average of the passed candidates was 39 and that of the failed candidates was 15, then the number of those candidates who passed the examination was

• A. 100
• B. 110
• C. 120
• D. 150

Answer 1

Answer: (A)

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=$120\times 35=4200.$

The total of the marks obtained by passed candidates=$39\times x=39x.$ and

the total of the marks obtained by failed candidates=$(120-x)\times 15=4200.$

Then the total=$39x+(120-x)\times 15=4200⟹24x=4200-1800⟹x=100$

So the number of passed candidates=100.

Ans- Option A.