the average monthly salary of 12 workers and 3 managers in a factory was Rs. 600. When one of the manager whose salary was Rs. 720, was replaced with a new manager, then the average salary of the team went down to 580. What is the salary of the new manager? Choose the correct choice from the following.
A) 640 B) 690 C) 420 D) 570 E) None
Solution:   The total salary amount = 15 � 600 = 9000   The salary of the exiting manager = 720.   Therefore, the salary of 12 workers and the remaining 2 managers,   = 9000−720 = 8280   When a new manager joins, the new average salary drops to Rs.580 for the total team of 15 of them.   The total salary for the 15 people i.e., 12 workers, 2 old managers and 1 new manager =580�15 =8700   Therefore, the salary of the new manager is,   9000 - 8700= 
<gadget id="calculator">9000 - 8700</gadget>
<output>300</output>
300 less than that of the old manager who left the company, which is equal to  720 - 300= 
<gadget id="calculator"> 720 - 300</gadget>
<output>420</output>
420.   Answer: Option 420
<result>C</result>
the average monthly salary of 12 workers and 3 managers in a factory was Rs. 600. When one of the manager whose salary was Rs. 720, was replaced with a new manager, then the average salary of the team went down to 580. What is the salary of the new manager?