At the beginning of the year, Savannah had $90 in savings and saved an additional
$10 each week thereafter. Isaac started the year with $50 and saved $20 every week.
Let S represent the amount of money Savannah has saved t weeks after the
beginning of the year and let I represent the amount of money Isaac has saved t
weeks after the beginning of the year. Graph each function and determine the who
has more money saved after 6 weeks.