Answer:
E
Step-by-step explanation:
Let's let c denote the amount of cashews and let's let p denote the amount of peanuts.
So, the owner wants to mix cashews worth $5.50 per pound with peanuts worth $2.30 per pound to get a 1/2 pound mixture that is worth $2.80 per pound.
In other words, the total pounds as an equation is:

Also, the price would be:

Since we mixed the peanuts and cashews, our sum would be 2.8(p+c).
And we already determined that p+c is 0.5. Thus, substitute:

Simplify:

Now, we can solve the system of equations. Isolate a variable from the very first equation:

Subtract p from both sides:

Now, substitute this into the equation earlier:

Distribute:

Combine like terms:

Subtract both sides by 2.75:

Divide everything by -3.2:
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Now, find c:

Substitute:

Subtract:

Thus, the owner would need 0.08 pounds of cashews and 0.42 pounds of peanuts.
Our answer is E.