average of money that group of 4 friends pay for rent each month is $ 800 . after one persons rent is increased by 25 % the new mean is $ 850 . what was original rent of friend whose rent is increased ?
"0.25 x = 4 ( 850 - 800 ) 0.25 x = 200 x = 800 answer a"
divide(multiply(subtract(850, 800), 4), divide(25, const_100))