a) We have to find how much more money she will earn if she deposits the money in a savings account rather than in the checking account.
If we use the graph, this is the difference, in the vertical axis, of the blue line (savings account) with the red line (checking account).
The time is 20 years, so we will place the vertical line at t = 20.
We then can find this segment in the graph as:
The principal for the savings account will be $32,000 after 20 years, while for the checking it will still be $16,000, so the difference is 32,000-16,000 = 16,000.
NOTE: each tick represents a difference of 2,000. This scale can cary from graph to graph. We have to look at the consecutive values and the number of divisions it has between them to see how much each tick represents.
b) We can estimate this also from the graph.
We will compare horizontal lines now, for a value = 30,000.
We have to find the difference in time for the retirement account (green line) and the savings account (blue line).
We can do it in the graph as:
In this case,each tick represents one year.
The retirement account reaches $30,000 in 9 years, while the savings account reaches it after 18 years. Then, the difference is 18-9 = 9 years.
Answer
1) $16,000
2) 9 years