The Pharmaceutical Journal
Vol 269 No 7229 pxxx
21/28 December 2002

This article
Reprint
Photocopy

The student pharmacist's brain teaser

In the days before the adoption of the metric system, pharmacy students taking a dispensing examination would frequently encounter a question similar to the one below. See if you can arrive at the right answer. One teaspoonful is regarded as one fluid drachm of liquid.

Dispense 6 fl oz of a solution of potassium permanganate so that one teaspoonful of the solution diluted to four pints with water will produce a 1:10,000 solution for topical use. Show your workings and state what amount of permanganate you used to make up your solution.

The answer to this brain teaser is 168 grains or 2 drachms 48 grains