The average (arithmetic mean) monthly income of four workers is $1,000. After one worker’s income increases by 50 percent the new average income is $1,200. What was the original income of the worker whose monthly income increased?	Choose the correct choice from the following answers.
A) $1,800  B) $1,500  C) $1,300  D) $1,600  E) $1,100
Increase in total income was 200*4= 
<gadget id="calculator">200*4</gadget>
<output>800</output>
$800, we know that this increase was 50% (1/2) of the workers original income, thus his/her original income was 800*2=$1,600.   Answer: $1,600
<result>D</result>
The average (arithmetic mean) monthly income of four workers is $1,000. After one worker’s income increases by 50 percent the new average income is $1,200. What was the original income of the worker whose monthly income increased?