Two tutors have given me the answer 400 mg, but that is incorrect.

PRINCIPEN' 250' III for ORAL SUSPENSION SQUIBB Ampicillin for Oral Suspension U.S.P. Bottle contains ampicillin trihydrate equivalent to 10 grams ampicillin in a dry, pleasantly flavored mixture. 200 ml. NDC 0003-0972-61 When prepared as directed each 5 ml. after mixing teaspoonful contains ampicillin trihydrate 250 mg. per 5 ml. equivalent to 250 mg. ampicillin. DIRECTIONS FOR PREPARATION when mixed as directed Use 118 ml. of water to prepare 200 ml. oral suspension: (1) Loosen powder. PRINCIPEN'250' (2) Add measured water and shake vigorously. for ORAL SUSPENSION Usual dosage: Adults, and children Ampicillin for weighing over 20 kg.; 250 mg. to 500 mg. q.i.d. in equally spaced doses. Children Oral Suspension U.S.P. weighing 20 kg. or less; 100 mg./kg./day q.i.d. in equally spaced doses. See insert Store at room temperature in dry form Caution: Federal law prohibits E. R. Squibb & Sons, Inc. dispensing without prescription Princeton, N.J. 08540 Made in U.S.A. M3906A What is the recommended daily dosage for a child weighing 9 lb? Write the numerical answer rounded to the nearest 100th followed by a space, them the unit