Final answer:
To earn an extra $1,000 for the trip to the Mathematics Museum in NYC, Mr. Foco's class needs to sell 211 sets of Special Gold Edition Dixon Ticonderoga pencil sets.
Step-by-step explanation:
In order to earn an extra $1,000 for the trip, we need to determine how many sets of pencils need to be sold. Each set costs $7.50 to purchase, with $2.75 going towards the cost of each set and an additional $39.98 for shipping. Let's calculate the profit per set:
- Profit per set = Selling price per set - Cost per set = $7.50 - $2.75 = $4.75
- To earn an extra $1,000, we need to divide the total profit needed by the profit per set: Total profit needed / Profit per set = $1,000 / $4.75 = 210.53
Since we cannot sell a fraction of a set, we need to round up to the nearest whole number. Therefore, we need to sell 211 sets to earn an extra $1,000 for the trip.