Answer:
9 students
Step-by-step explanation:
If 1 student runs a 3rd we need 3 students to run 1 mile.
Since we need 3 times that amount of miles we multiply the amount of students it takes to run 1 mile so that we find out how many we need to run 3 miles.
3 x 3 = 9
They will need 9 students I hope this helps have a great day :)