First, let's review what the "factorial operator" ! means.
5! = 5*4*3*2*1.
3! = 3*2*1
7! = 7*6*5*4*3*2*1
Then:
7! 7*6*5*4*3*2*1 7*6*5*4 5040
----- = ----------------------- = ------------- = ----------- = 5040 (answer)
3! 3*2*1 1 1
According to my calculations, after 200 miles, the prices will be equal.
From the 8th to the 13th there are five numbers, and the difference between the 8th and the 13th is 20-12.5=7.5, so the difference between two neighboring number is 7.5÷5=1.5
from the 13th and the 25th there are 12 numbers, so the total difference is 12*1.5=18
so the 25th term is 20+18=38
The answer to that one is the first box definitely
