In Company B, the total monthly payroll for the 20 factory workers is $36,000 and the total monthly payroll for the 50 office workers is $110,000. By how much does the average (arithmetic mean) monthly salary of an office worker exceed that of a factory worker in this company?  Answers
A) $400	B) $450	C) $500	D) $550	E) $600
The average monthly salary of a factory worker is: $36,000 / 20 = $1800.   The average monthly salary of an office worker is: $110,000 / 50 = $2200.   The difference in average salary is: $2200 - $1800 = $400.   The answer is $400.  2200 -  1800= 
<gadget id="calculator">  2200 -  1800</gadget>
<output>400</output>
$400.   The answer is $400.
<result>A</result>
In Company B, the total monthly payroll for the 20 factory workers is $36,000 and the total monthly payroll for the 50 office workers is $110,000. By how much does the average (arithmetic mean) monthly salary of an office worker exceed that of a factory worker in this company?