Types of Students in Examination Hall

The marks of 20 students in an examination are given in the following table. Average marks of these student is:

Which of the following can affect the results of student in the examination?

The average marks obtained by 120 students in an examination is 30. If the average marks of passed students is 40 and that of the failed students is 10, what is the 25% of the number of students who passed the examination?

The average marks obtained by 150 students in an examination is 40. If the average marks of passed students is 60 and that of the failed students is 20, then what is the number of students who passed the examination?

In an examination,30% and 35% students respectively failed in History and Geography while 27% students failed in both the subjects. If the number of students passing the examination is 248, find the total number of students who appeared in the examination.380 b.400 c.425 d.725