Answer:
67 sandwiches
Explanation:
If you invest 250 dollars to start, you're currently -250. If you gain 5.25 per sandwich you sell, you'd need to sell about 67 sandwiches.
I'm not entirely sure what your question meant though. If the question is simply asking how many sandwiches it would take to make 100 dollars, it would be about 20 sandwiches. If the question is asking how many sandwiches you'd need to sell to gain 100 dollars in profit, covering the cost of the cart, it would be about 67 sandwiches.