If the average marks of two sections of 40 and 45 students respectively is 75 and 60, then the average marks of all the students is:
Options:
A) 53.33
B) 67.05
C) 75
D) None of these
E) Cannot be determined
Explanation :   Required average = (40 x 75 + 45 x 60)/(40 + 45)   = (3000 + 2700)/85   = 5700/85   = 67.05   Answer : 67.05
<result>B</result>
If the average marks of two sections of 40 and 45 students respectively is 75 and 60, then the average marks of all the students is: