A school has four sections of chemistry in class XII having 40, 35, 45 and 42 students. The mean marks obtained in chemistry test are 50, 60, 55 and 45 respectively for the four sections, the over all average of marks per students is
Options:
A . 53
B . 45
C . 55.3
D . 52.25
Answer: Option D : D Total number of students =40+35+45+42=162 Total marks obtained =(40×50)+(35×60)+(45×55)+(42×45) =8465 Overall average of marks per students =8465162=52.25
