The average salary per head of the entire staff of a small factory including managers and technicians is Rs. 5750.
The average salary per head of a manager is Rs. 20000
and that of a technician is Rs. 5000.
If there are 4 managers, then the number of technicians in the factory is :

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.