Chapter 1 - Section 1.7 - Problem Solving: Interest, Mixture, Uniform Motion, Constant Rate Job Applications - 1.7 Asses Your Understanding - Page 141: 25

160 pounds

Let $x$ be the pounds of cashews, then $x+60$ is the amount in the mixture. Then our equation is: $9x+3.5\cdot60=7.5(x+60)\\9x+210=7.5x=450\\1.5x=240\\x=160$ Thus we have to mix 160 pounds of cashews in the mixture.