Since the graph is a straight line, its equation is of the form;

Where m is the slope and c is the y intercept
We can use any two points on the straight line to find the value of m and c.
Let us use (0,30) and (4,150)

This simplifies to,

Let us substitute the value of m to obtain,

Substitute any of the points to find c. It is easier to use (0,30).


The equation of the graph now becomes,

So in 10 weeks Ben will collect,



Ben will collect 330 papers.
You can also use any two points to find the equation of this line.