Mean = The sum of all observations/Total number of observations
∴ The sum of all observations = Mean x
Total number of observations
The mean salary of 20 workers is Rs 10,250.
∴ Sum of the salaries of 20 workers = 20 x 10,250
= Rs 2,05,000 …(i)
If the superintendent’s salary is added, then mean increases by 750 new mean = 10, 250 + 750 = 11,000
Total number of people after adding superintendent = 20 + 1 = 21
∴ Sum of the salaries including the superintendent’s salary = 21 x 11,000 = Rs 2,31,000 …(ii)
∴ Superintendent salary = sum of the salaries including superintendent’s salary – sum of salaries of 20 workers
= 2, 31,00 – 2,05,000 …[From (i) and (ii)]
= 26,000
∴ The salary of the office superintendent is Rs 26,000.
