on a certain farm the ratio of horses to cows is 5 : 1 . if the farm were to sell 15 horses and buy 15 cows , the ratio of horses to cows would then be 17 : 7 . after the transaction , how many more horses than cows would the farm own ?
originally , there were 5 k horses and k cows . 7 ( 5 k - 15 ) = 17 ( k + 15 ) 35 k - 17 k = 255 + 105 18 k = 360 k = 20 the difference between horses and cows is ( 5 k - 15 ) - ( k + 15 ) = 4 k - 30 = 50 the answer is c .
subtract(subtract(multiply(5, divide(add(multiply(15, 17), multiply(15, 7)), subtract(multiply(5, 7), 17))), 15), add(divide(add(multiply(15, 17), multiply(15, 7)), subtract(multiply(5, 7), 17)), 15))