The average marks obtained by 100 candidates in an examination is 50. Find how many candidates have passed in the examination, if the average marks of candidates who passed is 70 and that of failed candidates is 20.  Choose the correct choice:  A) 33  B) 77  C) 60  D) 29  E) 11
Explanation:   Let the number of students who passed the examination be X   Number of students failed = (100 - X)   Total marks of students who have passed = 70X   Total marks of 100 students = 100 * 50= 
<gadget id="calculator">100 * 50</gadget>
<output>5_000</output>
5000   Total marks of students who have failed= 20(100 – X)   20(100 – X) + 70X = 5000   2000 – 20 X + 70X = 5000   50 X = 3000   X = 60   ANSWER: 60
<result>C</result>
The average marks obtained by 100 candidates in an examination is 50. Find how many candidates have passed in the examination, if the average marks of candidates who passed is 70 and that of failed candidates is 20.