Wow, that's poor notation$^\dagger$ they have in the question; it doesn't distinguish which draw the events apply to properly. Before you draw any cards you have 26 red cards, 13 clubs (and 13 spades). After the first draw is red, they say you replace it (presumably shuffling again), so you *still* have 26 red cards, 13 clubs and 13 spades. At the second draw there are 52 cards, of which 13 are clubs; the chance of drawing a club is $\frac{13}{52}$. (Since the first-drawn card was replaced it changes nothing; you're exactly in the situation you started with) $\dagger$ A better notation would be: *Let R_i be the event "a red card was drawn at the $i$th card draw" and let C_i be the event "a club was drawn at the $i$th card draw*; then the problem is "What is $P(C_2|R_1)$?" which is useful to distinguish from various other possible questions. Ambiguous notation is a recipe for confusion.