An allergy test produces a single numeric score which contains the information about all the allergies the person has (that they were tested for).
The list of items (and their value) that were tested are:
eggs (1)
peanuts (2)
shellfish (4)
strawberries (8)
tomatoes (16)
chocolate (32)
pollen (64)
cats (128)
So if Tom is allergic to peanuts and chocolate, he gets a score of 34.
Now, given just that score of 34, your program should be able to say:
Whether Tom is allergic to any one of those allergens listed above. All the allergens Tom is allergic to.