An experiment that involves learning in animals requires placing white mice and rabbits into separate, controlled environments, environment I and environment II. The maximum amount of time available in environment I is 500 minutes, and the maximum amount of time available in environment II is 600 minutes. The white mice must spend 10 minutes in environment I and 25 minutes in environment II, and the rabbits must spend 15 minutes in environment I and 15 minutes in environment II.

(a) Write a system of inequalities that describes the constraints on the number of each type of animal used in the experiment. Begin by identifying what x and y represent.

(b) Graph the solution of the system of inequalities and find the corners of the solution region.