CPM Homework Help : AC Problem 2-98

Since the beginning of school, Steven has been saving money to buy a new MP3 player. His bank balance is represented by the graph below.

According to the graph, about how much money had Steven saved after $2$ weeks of school?
Hint (a):
Since the $x$ -axis represents the number of weeks of school, locate $x=2$ and move vertically along the line until you find the graphed point. What is the $y$ -coordinate for this point?
Answer (a):
He's saved about $$40.$
About how much money did Steven probably have after $4$ weeks of school? How can you tell?
Hint 1(b):
Imagine a line that best represents the trend of the graph.
Hint 2(b):
What is the $y$ -coordinate of the line when $x$ is $4$ ?
Answer (b):
about $$55$
If he keeps saving at the same rate, how much will he have saved by Week 7? Explain how you know.
Hint (c):
Follow the steps in part (b).

First quadrant graph: X, axis labeled, Weeks of School, Y, axis labeled, Bank Balance, with the following points: (0.5 comma 30), (1, comma 35), (1.5, comma 41), (2, comma 40), (2.5, comma 35,) and (5, comma 60).