A nurse is reviewing a new prescription for propranolol 200 mg PO daily divided in equal doses every 12 hr for a client who has migraine headaches during the premenstrual period. Available is propranolol solution 4 mg/mL. How many mL should the client self-administer per dose? (Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.)