If the average marks of 3classes of 55, 60 and 45 students respectively is 50, 55, 60, then find the average marksof all the students is Choose the correct choice from the following.
A) 53
B) 53.5
C) 54.68
D) 55.6
E) 67.2
Required average   = 55 x 50 + 60 x 55 + 45 x 60   55 + 60 + 45   = 2750 + 3300 + 2700   160   =	8750   160   = 54.68   54.68
<result>C</result>
If the average marks of 3classes of 55, 60 and 45 students respectively is 50, 55, 60, then find the average marksof all the students is