I don't understand how there would be 48 cards left if you took out 3 cards, wouldn't you have 49 cards?
but whatever rank the 3 of a kind was in, the fourth card of that rank can't be in the other two, or else you would have 4 of a kind, whatever they call that.
so we have to exclude 4 cards, not just the three from our triple.
(I actually used 49 in my first try also, but after not getting the answer you gave, did some more thinking about it)