Answer:
Between markers 3 and 4.
Step-by-step explanation:
We know that each student runs 2 / 11 miles. Given this, how many miles do the first two students run?
The answer is

Now, we know that the course has markers every 0.1 miles. How many markers are ther in 4 /11 miles?
The answer is


This is between markers 3 and 4. Meaning that the second student finishes between markers 3 and 4.