The possible numbers of additional miles he will run will be: [tex]t\geq 16[/tex]
Explanation
So far, Josh has run 19 miles and the number of additional miles he will run in this week is [tex]t[/tex] miles.
Given that, he will run at least total 35 miles this week. That means the minimum total distance, he will run in this week is 35 miles.
So, the inequality will be.....
[tex]t+19\geq 35\\ \\ t\geq 35-19\\ \\ t\geq 16[/tex]
Thus, he need to run at least 16 additional miles in this week.