Your question is incomplete, but I am guessing that it reads something like:
“Diego has run 4/5 of a race distance. He has run 7 2/3 miles. How long is the race? Or “how many miles does he have left?”
How long is the race? = 9 7/12 miles
4/5x = 7 2/3
4/5x = 23/3
x = 23/3 • 5/4
x = 115/12
x = 9.58333
x = 9 7/12 miles
How many miles does he have left? = 1 1/12 miles
1/5 • 115/12 = 115/60 = 1.916666
= 1 55/60 = 1 11/12 miles
Let me know if I didn’t guess your question correctly and I will try to help more.