A ratio is a mathematical expression that compares two numbers or quantities. In probability, ratios are often used to compare the number of favorable outcomes to the total number of possible outcomes. For example, when we want to determine the probability of drawing a red card from a deck, we start by writing this as a ratio:
- Number of red cards (favorable outcomes): 26
- Total number of cards in the deck (possible outcomes): 52
This gives us the ratio \( \frac{26}{52} \), indicating that out of every 52 cards, 26 are red. We can simplify this ratio by finding the greatest common divisor, which is 2 in this case, reducing it to \( \frac{13}{26} \). Ratios provide a foundational step in understanding and conveying probability.