Since the problem is given all the total walking distance, the first thing we are going to do is find the total distance in the map:


Now that we have the distance in the map, we can establish a ratio between the walking distance and the distance in the map:

We can conclude that each inch the map represents 0.5 miles of walking distance.
Answer:
Total compensation = 600 + 0.04 * s and a total last month of $1200
(which agrees with the second answer shown in the provided list)
Step-by-step explanation:
Total compensation comes from the addition of base salary ($600) plus 4% (0.04) of the sales (s). That means:
Total compensation = 600 + 0.04 * s
and since last month he brought $15000 in sales, he got from sales:
0.04 * 15000 = $600
which added to the base salary gives:
$600 + $600 = $1200
1.1, 1.3, 1.5. Your just adding .2 to the number each time