The average salary of the entire staff in the office is Rs. 120 per month. The average salary of officers is Rs. 460 and that of non- offic…

Let number of non-officers = a,

Then Total salary of officers = 15 × 460 = 6900,

Total salary of non-officers = a × 110.

Total salary of all employees = 120 × (15 +a)

Then,

Salary of all employees = Salary of officers + Salary of non-officers

120 × (15 + a) = 15 × 460 + 110a

1800 + 120a = 6900 + 110a

120a – 110a = 6900 – 1800

10a = 5100

a = 510

Hence, number of non-officers = 510