Question 22845
1)
 Use a proportion to find the number of mg, then convert to mcg.
 {{{40 mg/10 ml = x mg/2 ml}}}
{{{x = 8 mg}}}

Convert to micrograms: 1 mg = 1,000 mcg

{{{8 mg = 8000 mcg}}}

2)1 tablespoonful qid (four times a day) for 3 days (4 X 3) = 12 tablespoonsful. 

1 Tablespoonful = 15 ml approximately.  Perhaps your PDR has the exact conversion factor for this but I think it's more like 14.7868 ml per tbsp.

12 tbsp = 180 ml approximately. 
12 tbsp = 177.4412 ml more precisely.

3) Flow rate of 30 drops per minute over 6 hours (30 drops/min)(60 min/hr)(6 hrs) = 10,800 drops at 18 gtts/ml (18 drops/ml) = 600 ml.