Step-by-step explanation:
A. The inequality representing the cost limit is: \(0.25x + 0.75y \leq 3\).
B. To check if (1, 5) is a solution, substitute x=1 and y=5 into the inequality: \(0.25(1) + 0.75(5) \leq 3\). Evaluate this expression to see if it's true or false.