Final answer:
Emily's RSVP to the party represents the highest entropy with a 50% chance of attending, reflecting a state of unpredictability similar to a coin toss where random outcomes are more likely than ordered ones.
Step-by-step explanation:
When considering who has the highest entropy among RSVPs to a party where Mike has a 100% chance of coming, Emily has a 50% chance, and John has a 20% chance, we are essentially looking at the disorder or predictability of the outcome.
Entropy, in a thermodynamic sense, represents the measure of disorder or randomness in a system. In this context, Emily's attendance represents the highest entropy since there is equal probability of her attending or not attending, leading to a less predictable or more disordered situation.
Entropy increases when systems move from order to disorder, and in the example of coin tosses, there is a strong tendency for this to happen. Tossing coins will more likely lead to a random distribution than to the initial ordered state, illustrating the natural tendency toward increased entropy.
This concept is mirrored in the RSVP scenario where the uncertainty (or entropy) of attendees is evaluated on the basis of probability.