Peanuts cost $4/pound.
Cashews cost $9/pound.
Pecans cost $5.50/pound.
The final mixture cost is the amount of each nut by the cost of them by pound.
[tex]3pounds\cdot\frac{4}{\text{pound}}\text{ + 0.5pounds}\cdot\frac{9}{\text{pound}}\text{ + 1.5pounds}\cdot\frac{5.50}{\text{pound}}\text{ = 24.75 dollars}[/tex]The mixture cost $24.75
Then, by pound, we have to sum all the pounds:
3 + 0.5 + 1.5 = 5 pounds
[tex]\frac{24.75}{5}=\text{ 4.95}[/tex]The final result is $4.95 by pound.