Every day Amy travels 30 miles one-way to work. The park-and-ride where she catches the train is 5 miles from her home. The average speed of the train is 15 mph faster than the average speed in her car. Assuming she has no wait time for the train, her one-way trip takes 45 minutes. Find the speed of the car.

Astudent is determining the influence of different types of food on the growth rate of spiders. she feeds one group of spiders two caterpillars twice a week. the other group received similarly-sized beetles twice a week. she records the amount of time required for individuals to reach sexual maturity. her hypothesis is that the spiders feeding on caterpillars will have a faster growth rate because caterpillars have a higher protein content compared to beetles. in this experiment, what is the dependent variable? spiders assigned to different feeding groups. time required to reach sexual maturity number of prey items fed twice a week. growth rates of each group.