Answer:
-78 miles or 78 miles (depending on your question)
Step-by-step explanation:
I don't know any shortcuts for these, so I'm sorry if this isn't the technique you're looking for. I'll just do this in the most tedious way ever.
Step 1:
2240 / 28
2240/28 = 80
28/28 = 1
80 / 1
Step 2:
80 / 1
80 * 32 = 2560
1 * 32 = 32
2560 / 32
Step 3:
*If how many more miles for HUMPBACK*
2560 - 2638
-78 miles
*If how many more miles for GRAY*
2638 - 2560
78 miles