The average of marks obtained by 100 candidates in a

Solution

Let the number of students who passed the examination be ‘x’. Number of students who failed in the examination = 100 – x Total marks obtained by 100 candidates = 100 × 40 Total marks of passed candidates = 55x Total marks of failed candidates =35 × (100 - x) Total marks obtained by 100 candidates = Total marks of passed candidates + Total marks of failed candidates 100 × 40 = 55x + 35 × (100 - x) 55x + 35 × 100 – 35x = 100 × 40 20x = 100 × 40 – 100 × 35 20x = 100 × 5, x = 25 So, number of passed candidates = 25 Number of failed candidates = 100 – x = 100 – 25 = 75 Required ratio = 25: 75 = 1:3