Chapter 4.7, Problem 23P

You start a savings account with $200 and save $30 each month. Write an explicit formula to represent the amount of money you invest into your savings account as an arithmetic sequence. How much money will you have invested after 12 months?

To determine

To find:The formula and the money invested after 12 months.

Answer to Problem 23P

The formula is $I=\$200-\$30t$ and the value of the card after buying 8 coffees is 560

Explanation of Solution

Given:

The initial investment in saving account is $200

The per month deposit is $30

Calculation:

The required formula is,

  $I=\$200+\$30t$

Here, V is the total savings and t is months.

Substitute 12 for t in the above equation.

  $\begin{array}{c}I=\$200+\$30t\\ =\$200+\$30\left(12\right)\\ =\$560\end{array}$

Thus, theformula is $I=\$200-\$30t$ and the value of the card after buying 8 coffees is 560