The frequency distribution of the marks obtained in a school is given below. In the table, the number of students who obtained marks from 31 to 40 , is unknown . But it is known that the average of total work obtained by the students is 42.85. Find the lost frequency.

The step frequency distribution table of the marks obtained by female students is given below. Calculate the mean marks.

The frequency distributions of the weekly wages of some labourers of an industry are given below : The number of labourers having Rs. 25 weekly wages is unknown. But it is known that the average weekly wages of a labourer is Rs. 27.50 . Find the unknown frequency .

The frequency distribution of marks in Mathematics obtained by 50 students in an examination is given below. Find mode.

The arithmetic mean of the marks obtained in 8 different subjects in a school are given below. Find the average of the sum of the marks of 8 subjects.

The frequency distribution of the heights (in cm) of 100 students of class X in a school .Find the average height of the students .

The weights (in Kg) and their frequency distribution of 100 students are given below. Find their arithmetic mean.

Donations (in rupees) are given for a fare by the 100 students of a school. In the following table rate of donation and the number of students are given. In the above data, the rate of donation of 24 students is unknown , but it is known to us that the average rate of donation is Rs. 1.27 . Find teh unknown frequency.

The frequency distribution of the degre of the drugs of 110 patients to be cured are given below : Here the number of patients being cured by taking 20 tablets and the number of patients being cured by taking 32 tablets are unknown. But it is known that the number of tablets required to be cured per patient is 20 tablets. Find the two unknown frequencies.

Find the mean of obtained marks of the students from the following cumulative frequency of obtained marks.

The marks obtained by 41 students in an examination in Math are given below: Find the average of the marks obtained by them.