mixture a is 15 percent alcohol , and mixture b is 50 percent alcohol . if the two are poured together to create a 4 - gallon mixture that contains 30 percent alcohol , approximately how many gallons of mixture a are in the mixture ?
"ratio of a to b in the final mixture = 50 - 30 : 30 - 15 = 4 : 3 gallons of a used = 4 / 7 * 4 = 2.28 answer : c"
divide(divide(multiply(15, 50), 50), const_2)