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Problem of the Week
Problem B
Banking on Amir

Amir’s aunt wants to help him develop an education fund so that he can go to drumming school. He started a bank account with \(\$40\), and each month thereafter a \(\$20\) deposit is to be made.

The graph below shows how the bank account grows over time (with no interest).

A graph of Account Balance versus Number of Months with five data points plotted as follows: At 0 months, the account balance is 40; at 1 month, the balance is 60; at 2 months, it is 80; at 3 months, it is 100; and at 4 months, it is 120. The graph continues through to month 9 but no data points are plotted past month 4.

  1. Create a table of values, listing the five ordered pairs of coordinates from the graph, as indicated by the dots.

  2. What is the pattern rule for the monthly account balance? Use your rule to add as many points to the graph as possible.

  3. How much will Amir have in his account after \(6\) months? Show on the graph how you got your answer.

  4. After how many months will Amir have \(\$220\) in his account? Show on the graph how you got your answer.

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Themes: Algebra, Data Management