Chapter 5.1, Problem 58E

In Problems 55-66, express your answer as a linear inequality with appropriate nonnegative restrictions and draw its graph.

Fertilizer. A farmer wants to use two brands of fertilizer for his soyabean crop. Brand $A$ contains $18\text{\% nitrogen, }24\text{\% phosphate, and }12\text{\% potash}\text{.}$ Brand $B$ contains

$5\text{\% nitrogen, }10\text{\% phosphate, and }15\text{\% potash}\text{.}$

(Source: Spectrum Analytic, Inc.)

(A) How many pounds of each brand of fertilizer should he add to each acre if he wants to add at least $50$ pounds of phosphate to each acre?

(B) How many pounds of each brand of fertilizer should be add to each acre if he wants to add at most $60$ pounds of potash to each acre?