It is about Statistical Analysis for engineers, please help me answer this activty

3. The following is a distribution for the number of employees in 41'.) companies belonging to a certain industry. Calculate the following: a. Mean, median, and mode 11. First and third quartiles c. Third and ninth deciles d. Thirty-fifth and seventy-third percentiles No. of No. of Employees Companies 4. A company pays its 115 employees a mean monthly salary of Php10,500; a second one pays its 75 employees an average monthly salary of Php12,720; and a third company pays its 92 employees an average monthly salary of Php11,300. what is the average salary per employee in the three companies