For option 1:
Let:
y = Total money
t = Number of years
We can model the 1st option as:
[tex]y=1000.5t[/tex]Since you are 4 years old and she will give you money until you are 21, then:
[tex]\begin{gathered} t=21-4=17 \\ y=1000.5(17) \\ y=17008.5 \end{gathered}[/tex]You will have $17008.5 for the 1st option.
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For option 2: