Answer: Hello there!
in a deck of 52 cards, you have 26 red cards and 4 kings, where 2 kings are also red cards, so we could discard them.
We want to know the probability of drawing a red card or a king whem we draw at random, then all the cards have the same probability. This is the quotient between the number of red cards or kings and the total number of cards:
p = 26/52 + 2/52 = 28/52 = 0.48
then you have a 0.48 (or 48%) probability to get a red card or a king.