In a history examination, the average for the entire class was 80 marks. If 10% of the students scored 95 marks and 20% scored 90 marks, what was the average marks of the remaining students of the class? 


(a) 
65.5 
(b) 
72.5 
(c) 
75 
(d) 
85 
In a history examination, the average for the entire class was 80 marks. If 10% of the students scored 95 marks and 20% scored 90 marks, what was the average marks of the remaining students of the class? 


(a) 
65.5 
(b) 
72.5 
(c) 
75 
(d) 
85 
Let the numbers of students in the class be 100 and let the required average be
Then,