Chapter 5, Problem 14RE

Electronics. A company uses two machines to solder circuit boards, an oven and a wave soldering machine. A circuit board for a calculator needs $4$ minutes in the oven and $2$ minutes on the wave machine, while a circuit board for a toaster requires $3$ minutes in the oven and $1$ minute on the wave machine. (Source: Universal Electronics)

(A) How many circuit boards for calculators and toasters can be produced if the oven is available for $5$ hours? Express your answer as a linear inequality with appropriate non-negative restrictions and draw its graph.

(B) How many circuit boards for calculators and toasters can be produced if the wave machine is available for $2$ hours? Express your answer as a linear inequality with appropriate nonnegative restrictions and draw its graph.