For the high school’s production of "grease," 490 tickets were sold. The cost of a student ticket was $8, a pre-sale non-student ticket was $10, and a ticket at the door cost $12. The total income from ticket sales was $4600. The combined number of student and pre-sale tickets was 6 times more than the tickets sold at the door. Which system of equations could be used to determine the number of each type of ticket sold?.

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.