Where X, Y and Z are the variables for the medicine administered.
Step 1: X, Y and Z should suppress pain and / or Diarrhoea.
Aspirin / alcohol and lomotil need to be administered to all the three.
Step 2: X cannot aggravate peptic ulcer. This rules out aspirin. Therefore, Peter is administered alcohol for pain and lomotil for Diarrhoea.
Y cannot impair lever-function. This rules out lomotil. Therefore, Mary is administered either aspirin or alcohol.
Z cannot aggravate eczema. None of the medicines under consideration do that. Therefore, Frank can be administered any of the two pain killers and lomotil.
1. recommended (Peter, alcohol+lomotil)
2. recommended(Mary, aspirin) – there is no solution for diarrhoea.
3. recommended (Frank, aspirin+lomotil)