Answer:
t ≥ 18
Step-by-step explanation:
He has run 12 miles plus some more miles t. He need to run at least 30 miles
12+t ≥ 30
Subtract 12 from each side
12+t-12 ≥ 30-12
t 》18
t + 12 》30
t 》30 - 12
