The average salary of the entire staff in an office is ₹ 200 per day. The average salary of officers is ₹ 550 and that of non officers is ₹ 120. If the number of officers is 16, then find the number of non officers in the office.

Correct Answer: 70

Explanation:

Let the number of non-officers be y.
Then number of entire staff = 16 + y
Sum of total salary = 200(16 + y)
=16 x 550 + 120y
⇒ 120y + 550 x 16 = 200x16 + 200y
⇒ 3y +220 = 80 + 5y
⇒ 2y = 140
∴ y = 140/2 = 70