Benjamin's Backpacks can sell backpacks for $25 per backpack. The costs for making the backpacks are a fixed cost of $400 and a production cost of $15 per backpack (see Example 9 for an example of cost and revenue equations).

a) Write the cost and revenue equations.

b) Graph both equations, for up to and including 50 backpacks, on the same axes.

c) Use the graph to estimate the number of backpacks Benjamin’s Backpacks must sell to break even.

d) Write the profit formula.

e) Use the profit formula to determine whether Benjamin’s Backpacks makes a profit or loss if it sells 30 backpacks. What is the profit or loss?

f) How many backpacks must Benjamin’s Backpacks sell to make a profit of $1000?

Part of the question involves determining a system of equations that models the situation.