on a certain farm the ratio of horses to cows is 6 : 1 . if the farm were to sell 15 horses and buy 15 cows , the ratio of horses to cows would then be 3 : 1 . after the transaction , how many more horses than cows would the farm own ?
"originally , there were 6 k horses and k cows . ( 6 k - 15 ) = 3 ( k + 15 ) 6 k - 3 k = 45 + 15 3 k = 60 k = 20 the difference between horses and cows is ( 6 k - 15 ) - ( k + 15 ) = 5 k - 30 = 70 the answer is d ."
subtract(subtract(multiply(6, divide(add(multiply(15, 3), multiply(15, 1)), subtract(multiply(6, 1), 3))), 15), add(divide(add(multiply(15, 3), multiply(15, 1)), subtract(multiply(6, 1), 3)), 15))