The average (arithmetic mean) monthly income of four workers is $3,000. After one worker’s income increases by 20 percent the new average income is $3,300. What was the original income of the worker whose monthly income increased? Options
A) $6,500
B) $6,400
C) $6,000
D) $6,200
E) $6,600
Increase in total income was 300*4= 
<gadget id="calculator">300*4</gadget>
<output>1_200</output>
$1200, we know that this increase was 20% (1/5th) of the workers original income, thus his/her original income was 1200*5=$6,000.   Answer: $6,000
<result>C</result>
The average (arithmetic mean) monthly income of four workers is $3,000. After one worker’s income increases by 20 percent the new average income is $3,300. What was the original income of the worker whose monthly income increased?