Question

Jillian is saving for a trip to Disney World. She put $14 in her account and $4 in her account each additionalday. Write an explicit rule for this situation. How much money will she have after 35 days?

Answer 1

D. f(n) = 14 + 4(n - 1); 150

EXPLANTION :

Recall the formula for an arithmetic sequence :

`a_n=a_1+d(n-1)`

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 :

`f(n)=14+4(n-1)`

The amount of money in her account after 35 days is when n = 35

`\begin{gathered} f(35)=14+4(35-1) \\ f(35)=150 \end{gathered}`