Answer:
The answer is m = 150
Step-by-step explanation:
A - 700 = 250 + 3m
B - m = 150 miles
C - m = 150
3(150) + 250 = 700
↓ ↓ ↓ ↓ ↓
450 + 250 = 700
∨ ↓ ↓
700 = 700 ✓