When you have a 15 and the dealer shows a 10, the best strategy is to hit.
This is because the dealer’s 10 is a strong card, and they are likely to have a hand total of 20 if their face-down card is a 10 or a face card. If you stand on a 15, you risk the dealer completing their hand and beating you. By hitting, you give yourself a chance to improve your hand and avoid the potential of losing to the dealer's strong hand.
However, it's important to remember that a 15 is a risky hand to hit, as you could bust if you draw a high card (6 or higher). Still, statistically, hitting in this situation has a lower expected loss compared to standing.
This is because the dealer’s 10 is a strong card, and they are likely to have a hand total of 20 if their face-down card is a 10 or a face card. If you stand on a 15, you risk the dealer completing their hand and beating you. By hitting, you give yourself a chance to improve your hand and avoid the potential of losing to the dealer's strong hand.
However, it's important to remember that a 15 is a risky hand to hit, as you could bust if you draw a high card (6 or higher). Still, statistically, hitting in this situation has a lower expected loss compared to standing.