A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.

A class teacher has the following absentee record of 40 student of a class for the whole term. Find the mean number of days a student was absent. {:("Number of days ",0-6,6-10,10-14,14-20,20-28,28-38,38-40),("number of students "," "11," "10," "7," "4," "4," "3," "1):}

A class teacher has the following attendence record of 40 students of a class for the whole term. Find the mean number of days a student was present out of 56 days in the term.

A class teacher has the following attendance record of 40 students of a class of for the whole term . Find the mean number of days a student was present out of 56 days in the term . {:("Number of days","Number of students"),(35-38,1),(38-41,3),(41-44,4),(44-47,4),(47-50,7),(50-53,10),(53-56,11):}

Find the mean weight of 20 students in your class.

The age of 40 student of a class is given in the following table. Find their mean short cut method:

In a class of 40 students, 45% are girls. Find the number of boys in the class .

If 30 of the 36 students of a class were present on a certain day,what percentage of students were absent?