michael started a savings account with $300. after 4 weeks, he had $350, and after 9 weeks, he had $400. what us the rate of change of money in his savings account per week?
[tex]\begin{gathered} \text{rate of change =}\frac{change\text{ in y}}{\text{change in x}} \\ rate\text{ of change =}\frac{400-350}{9-4} \\ \text{rate of change =}\frac{50}{5} \\ \text{rate of change=10} \end{gathered}[/tex]
