p = pounds of pistachio pleasure
s = pounds of pistachio surprise
Kim wants a new mixture weighing 12 pounds:
p + s = 12
A pound of pleasure contains 0.8 pound of pistachios, and a pound of surprise contains 0.3 pound of pistachios. Each pound of the new mixture should contain 0.4 pound of pistachios, so the mix should contain 0.4 • 12 = 4.8 pounds:
0.8p + 0.3s = 4.8
Solve the system:
s = 12 - p
0.8p + 0.3(12 - p) = 4.8
0.8p + 3.6 - 0.3p = 4.8
0.5p = 1.2
p = 2.4
s = 12 - 2.4
s = 9.6
