Answer:
They earned more money in September by $30 dollars
Explanation:
The selling price of each flower is .375 dollars per flower, so if they sold 200 more, and the class earns 40% of the selling point we jut have to make the multiplications to know how much they earned for each flower:

No we just multiply that by the difference in the number of flowers sold:

And the answer is that they earned $30 more in september than in october.