<prompt> Calculate the profit earned from a sale of 10 items at 4 each with a cost of 0.50 for each item.  <response>: The total revenue from the sale of 10 items at 4 each is 10 4 40.The total cost of the 10 items at 0.50 each is 10 0.5 5.The profit is calculated by subtracting the total cost from the total revenue: 40 - 5 35.Therefore, the profit earned from this sale is 35. 