ANSWER :
D. f(n) = 14 + 4(n - 1); 150
EXPLANTION :
Recall the formula for an arithmetic sequence :
[tex]a_n=a_1+d(n-1)[/tex]
where an = nth term
a1 = first term
and
d = common difference
From the problem, the first term is a1 = $14, initial amount in her account
and the common difference is d = $4, amount that varies each day.
an will be f(n)
Using the formula above :
[tex]f(n)=14+4(n-1)[/tex]
The amount of money in her account after 35 days is when n = 35
[tex]\begin{gathered} f(35)=14+4(35-1) \\ f(35)=150 \end{gathered}[/tex]
