Acollege writing seminar increased its size by 5o% from the first to the second day. if the total number of students in the seminar on the second day was 15, how many students were in the class on the first day?

Spider crabs live in the shallow regions of the ocean floor. algae tend to grow on the surface of spider crabs. the algae provide the crabs protection from predators by camouflaging them. the spider crabs give the algae shelter. what does this description suggest? 1. the algae are parasites of the spider crabs. 2. the algae and the spider crabs have a mutualistic relationship. 3. the spider crabs are commensals, and the algae are parasites. 4. the spider crabs benefit from the algae living on them. 5. the spider crabs are parasites of the algae.