Im doing a small project in math, and this is what the main things to know are: Kerri has saved all of her money in one large piggy bank. One day Kerri decides to start spending her money and she begins taking out the same amount of money every day.
Kerri knows that 17 days after she started spending her money she had $325.50 left in her piggy bank. She also knows that 37 days after she started spending her money she had $150.50 left.

For one of the questions, I have to find the constant rate of change for this. Does anyone know how to solve this? any help would be very appreciated! thank you!