Problem: average of money that group of 4 friends pay for rent each month is $ 800 . after one persons rent is increased by 20 % the new mean is $ 860 . what was original rent of friend whose rent is increased ?
Rationale: "0.2 x = 4 ( 860 - 800 ) 0.2 x = 240 x = 1200 answer e"
annotated_formula: divide(multiply(subtract(860, 800), 4), divide(20, const_100))