It's a little hard to interpret, isn't it?
The problem is as simple (mathematically) as it looked to me, which seemed too trivial!thanks for responding - really appreciated. The answer for this is 60%, which suggests that the number of cards needed is 3, and so the fraction is 3/5. But I can't think why this can't be 4 or 5 brand new distinct cards over 5 cards (i.e. 5/5 = 100%).
Part (b) of the question just asked to convert the fractions into percentages (i.e. 4/5 = 80%)