Final answer:
The electrician's profit is $27.
Step-by-step explanation:
To calculate the profit of the electrician, we need to consider both the cost and the revenue.
The electrician bought 100 units of armored cable connectors at $2.10 each, which amounts to a total cost of $210.
He sells them at a price of $3.00 per unit, so his total revenue is $300.
His overhead is 30% of the cost, which is $210 * 0.30 = $63.
Therefore, his profit is the total revenue minus the cost and overhead: $300 - $210 - $63 = $27.