52 cards total
26 are red
so you would have a 26/52 reduced to 1/2 probability of picking a red one.
There are 4 aces so you would have a 4/52 reduced to 1/13 probability of picking an ace.
There are 2 red aces so you would have a 2/52 reduced to 1/26 probability of picking a red Ace
