Students of three different classes appeared in common examination. Pass average of 10 students of first class was 60%, pass average of 15 students of second class was 60% and pass average of 25 students of third class was 80% then what will be the pass average of all students of three classes?	Choose one: A) 74% B) 75% C) 69% D) 70% E) None
Solution:   Sum of pass students of first, second and third class,   = (60% of 10) + (60% of 15)+ (80% of 25)   = 6+9+20= 
<gadget id="calculator">6+9+20</gadget>
<output>35</output>
35   Total students appeared,= 10+15+25= 
<gadget id="calculator">10+15+25</gadget>
<output>50</output>
50   Pass average,= 35*100/50= 
<gadget id="calculator">35*100/50</gadget>
<output>70</output>
70%.   Answer: Option 70%
<result>D</result>
Students of three different classes appeared in common examination. Pass average of 10 students of first class was 60%, pass average of 15 students of second class was 60% and pass average of 25 students of third class was 80% then what will be the pass average of all students of three classes?