nut store normally sells cashews for? $4.00 per pound and peanuts for? $1.50 per pound. But at the end of the month the peanuts had not sold? well, so, in order to sell 20 pounds of peanuts, the manager decided to mix the 20 pounds of peanuts with some cashews and sell the mixture for $2.00 per pound. How many pounds of cashews should be mixed with the peanuts to ensure no change in the profit?

To determine how many pounds of cashews should be mixed with the peanuts to ensure no change in profit, let's first understand the costs and selling prices of each type of nut.

1. **Costs:**
- Cost of peanuts: $1.50 per pound
- Cost of cashews: $4.00 per pound

2. **Peanuts being sold:**
- Total pounds of peanuts = 20 pounds
- Total cost of peanuts = \( 20 \text{ pounds} \times 1.50 \text{ dollars/pound} = 30 \text{ dollars} \)

3. **Selling price for the mixture:**
- The manager wants to sell the mixture for $2.00 per pound.

Let \( x \) be the number of pounds of cashews to mix with the 20 pounds of peanuts. The total weight of the mixture will be \( 20 + x \) pounds.

4. **Total selling price of the mixture:**
- Total selling price for the mixture = \( (20 + x) \text{ pounds} \times 2 \text{ dollars/pound} = 40 + 2x \text{ dollars} \)

5. **Cost of the cashews:**
- Total cost of cashews = \( x \text{ pounds} \times 4 \text{ dollars/pound} = 4x \text{ dollars} \)

6. **Total cost of the mixture:**
- Total cost = Cost of peanuts + Cost of cashews
\[
\text{Total cost} = 30 \text{ dollars} + 4x \text{ dollars}
\]

7. **Setting up the equation:**
To ensure no change in profit, the total selling price should equal the total cost:
\[
40 + 2x = 30 + 4x
\]

8. **Solving for \( x \):**
\[
40 + 2x - 2x = 30 + 4x - 2x \\
40 = 30 + 2x \\
40 - 30 = 2x \\
10 = 2x \\
x = 5
\]

Thus, the manager should mix **5 pounds of cashews** with the 20 pounds of peanuts to ensure no change in profit.