Respuesta :
Derek ran less than 6 miles. If the race is 6 miles, and he only ran 3/8, he ran less than a half of the race. If he didn't finish the race of 6 miles, he couldn't possibly have run 6 miles.
He took less than because 8/8 would be the whole, and 3/8 is less than 8/8, or 1 whole.
Glad I could help, and good luck! :)
Glad I could help, and good luck! :)