The average monthly salary of 9 workers and one supervisor in a factory was…
2025
The average monthly salary of 9 workers and one supervisor in a factory was Rs. 8700 per month. After retiring of a worker, a new supervisor was appointed and the average salary of 10 people was Rs. 8900 per month, then the difference between the monthly salary of a worker and a supervisor is ___
- A.
Rs. 3000
- B.
Rs. 1500
- C.
Rs. 2500
- D.
Rs. 2000
Attempted by 15 students.
Show answer & explanation
Correct answer: D
Let W = monthly salary of a worker and S = monthly salary of a supervisor.
Initial total salary for 9 workers and 1 supervisor = 10 × 8700 = 87000, so 9W + S = 87000.
After one worker retires and a new supervisor is appointed, the group becomes 8 workers and 2 supervisors. New total = 10 × 8900 = 89000, so 8W + 2S = 89000.
Solve the system: multiply the first equation by 2 to get 18W + 2S = 174000. Subtract the second equation (8W + 2S = 89000) to get 10W = 85000, so W = 8500.
Substitute W = 8500 into 9W + S = 87000: 9 × 8500 + S = 87000 ⇒ 76500 + S = 87000 ⇒ S = 10500.
Difference between supervisor and worker = 10500 − 8500 = 2000.
Answer: Rs. 2000