As a nurse, part of your daily duties is to mix medications in the proper proportions for your patients. for one of your regular patients, you always mix medication a with medication b in the same proportion. last week, your patient's doctor indicated that you should mix 90 milligrams of medication a with 45 milligrams of medication b. however this week, the doctor said to only use 30 milligrams of medication b. how many milligrams of medication a should be mixed this week?