The frequency distributions of the weekly wages of some labourers of an industry are given below :
Channel: Doubtnut
Date: 10/05/2020

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 .