To find the cost per pound of apples, you can divide the total cost by the total weight in pounds.
Given that 4 pounds of apples cost $6, you can calculate the cost per pound as follows:
\[ \text{Cost per pound} = \frac{\text{Total cost}}{\text{Total weight}} = \frac{6}{4} = 1.5 \]
So, the cost per pound of apples is $1.50.