If the average marks of three batches of 50, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is Select
A) 53.33  B) 54.83  C) 55  D) 57  E) None
Sol.   Required average = [50x50 + 60x55 + 45x60 / 50 + 60 + 45]   = [2500 + 3300 + 2700 / 155]   = 8500 / 155 = 54.83.   Answer 54.83
<result>B</result>
If the average marks of three batches of 50, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is