Pedro le dice a maría si cambias los billetes de 10 € que tienes por billetes de 5 € y los billetes de 5 € por billetes de 10 € seguirás teniendo el mismo dinero cuánto dinero tiene maría si en total son 20 billetes

If a 36 inch yardstick casts a 21 foot shadow, how tall is a building whose shadow is 168 feet? what is the scale factor

How can constraints be used to model a real-world situation?

Naruto is choosing between two venues that will deliver food to his house. with probability 1/3 he will choose ramen mania (r), and with probability 2/3 he will choose sushi (s). if he chooses r, 15 minutes after making the call, the remaining time it takes the food to arrive is exponentially distributed with average 10 minutes. if he orders s, 10 minutes after making the call, the time it takes the food to arrive is exponentially distributed with an average of 12 minutes. given that he has already waited 25 minutes after calling, and the food has not arrived, what is the probability that he ordered from r? i am really stuck on how to set this up, so if you could be extra clear, that would be super ! in advance