Answer:
25/51
Explanation:
If the first card was a heart, we've drawn one red card already.
The ratio of black to red cards in the deck is now 26:25.
On the second draw, there will be only 51 cards to choose from, rather than 52 because you have already taken out a card. Therefore, you only have a 25/51 chance of drawing a red card compared to the 26/52 or 1/2 chance on the first draw.
Answer is 25/51.