Answer
a)
$10 \leq x+y$
$x+y\leq20$
$x \geq 2$
$25x+.4y \leq90$
Please see the graph.
b) Answers may vary, but one possible answer is as follows:
$x=3$, $y=12$ mass is 15 grams, cost of gold is 75 dollars, cost of silver is 4.80 (total cost is $79.80)
Work Step by Step
a) x = grams of gold, y = grams of silver
The graph was made using graphing software.
$10 \leq x+y$
$x+y\leq20$
$x \geq 2$
$25x+.4y \leq90$
b) $3+12= 15$ $3*25 + 12*.4 = cost$ $75 + 4.8 = 79.8 = cost$
