To find the percentage of students who passed:
Step 1: Calculate the number of students who passed in each class
Class 1: 50 × 0.8 = 40 students
Class 2: 60 × 0.7 = 42 students
Class 3: 70 × 0.6 = 42 students
Step 2: Calculate the total number of students who passed
40 + 42 + 42 = 124 students
Step 3: Calculate the total number of students in the school
50 + 60 + 70 = 180 students
Step 4: Calculate the percentage of students who passed
(124 / 180) × 100% ≈ 68.89%
So, the percentage of students who passed in the examination from the entire school is:
68.89%
