Final answer:
The probability that the second card is blue, given that the first is red, is 10/19.
Step-by-step explanation:
To find the probability that the second card is blue, given that the first card is red, we need to consider the reduced sample space after selecting a red card. Initially, there are 10 red cards and 10 blue cards, making a total of 20 cards. After selecting a red card, there are 9 red cards and 10 blue cards left. Therefore, the probability of selecting a blue card as the second card, given that the first card is red, is 10/19.