Amy bakes muffins for her friends. On Monday, she brings 1 muffin to school to share. Each day for the rest of the week she brings one more muffin to school than she did the day before. If on Saturday she counts that there are 7 muffins left, how many did she originally bake? Give me reasons, before answering the question
On Tuesday, she brings in 1 + 1 = 2 muffins. On Wednesday, she brings in 2 + 1 = 3 muffins. On Thursday, she brings in 3 + 1 = 4 muffins. On Friday, she brings in 4 + 1 = 5 muffins. In total, she brought 1 + 2 + 3 + 4 + 5 = 15 muffins to school to share with her friends. She baked a total of 15 + 7 = 22 muffins. So the final answer is 22.