Final answer:
Gordon needs to sell 30 more bags of popcorn at $7.50 each to reach his goal of over $300 and win a prize.
Step-by-step explanation:
Gordon has already sold $75 worth of popcorn. To win a prize, he needs to sell over $300 in total. The cost of one bag of popcorn is $7.50. The amount he still needs to sell to reach his goal is $300 - $75 = $225. Now we need to calculate how many more bags he needs to sell to reach the additional $225.
To find out how many bags of popcorn are required to make $225, we divide the total amount needed by the cost per bag: $225 ÷ $7.50 = 30 bags.
Therefore, Gordon needs to sell 30 more bags of popcorn to win the prize.