Elia rode her bicycle from her house to the beach at a constant speed of 181818 kilometers per hour, and then rode from the beach to the park at a constant speed of 151515 kilometers per hour. The total duration of the rides was 111 hour and the distances she rode in each direction are equal. Let bbb be the number of hours it took Elia to ride from her house to the beach, and ppp the number of hours it took her to ride from the beach to the park.

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