Answer:
[tex](f + g)(t) = f(t) + g(t) = 14375 (1 + \frac{5.3}{100})^{t} + 6840t[/tex]
$29619.13
Step-by-step explanation:
a. Tara has $14375 in credit card debt and the interest rate is 5.3%.
Now, if f(t) represent the amount of money Tara have in credit card debt, where t is the number of years after after interest begins to accrue, then
[tex]f(t) = 14375 (1 + \frac{5.3}{100})^{t}[/tex] ......... (1)
Again Tara borrows $570 each month for rent from her parents without any interest.
If g(x) represent the amount of money Tara owes to her parents, where t represents the number of years passed,then we can write
g(t) = 570 × 12t = 6840t ........ (2)
Therefore, [tex](f + g)(t) = f(t) + g(t) = 14375 (1 + \frac{5.3}{100})^{t} + 6840t[/tex]
b. So, for t = 2 years,
[tex](f + g)(t) = 14375 (1 + \frac{5.3}{100})^{2} + 6840 \times 2[/tex] = $29619.13
So, Tara has to repay $29619.13 if she continues this way without any repayment for 2 years. (Answer)