Given:
the Central location used 160 notepads
We will use the graph and the table to find the relation between the number of notepads and the number of departments per location
From the graph, in the Central location reach line 4
This means each line represents 160/4 notepads = 40 notepads
For the Midtown, it reaches line 3
So, the number of notepads = 3 * 40 = 120 notepads
From the table: the number of the department of Midtown = 4
So, the number of notepads per department = 120/4 = 30
So, the answer will be 1: 30