the average ( arithmetic mean ) monthly income of 4 workers is $ 1000 . after one worker ’ s income increases by 50 percent the new average income is $ 1200 . what was the original income of the worker whose monthly income increased ?
increase in total income was 200 * 4 = $ 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 : d
subtract(subtract(subtract(multiply(1200, 4), multiply(subtract(4, const_1), 1000)), divide(subtract(multiply(1200, 4), multiply(subtract(4, const_1), 1000)), add(divide(50, const_100), const_1))), const_100)