If a 30-pound spool of copper wire costs $78 and the empty spool weighs 4 pounds, what is the approximate price per pound of copper wire?

To determine the price per pound of copper wire, you first need to calculate the actual weight of the copper wire without the weight of the empty spool. Since the total weight of the spool with the wire is 30 pounds, and the weight of the empty spool is 4 pounds, you can find the weight of just the copper wire by subtracting the weight of the spool from the total weight.

30 pounds (total weight) - 4 pounds (weight of the empty spool) = 26 pounds (weight of the copper wire).

Next, to find the price per pound, you divide the total cost of the copper wire by the weight of the copper wire:

$78 (cost of the copper wire) ÷ 26 pounds = $3.00 per pound.

This calculation confirms that the price per pound of copper wire is approximately $3.00, which aligns with the choice indicating this amount. Understanding the components of the problem and performing the calculations accurately leads to the conclusion that $3.00 reflects the cost per pound of the copper wire on its own, excluding the spool.