a = 4800 – 6t
b = 5400 – 8t
In the system of equations above, a and b represent the distance, in meters, two marathon runners are from the finish line after running for four hours and t seconds. How far will runner a be from the finish line when runner b passes her?
A. 300 meters
B. 500 meters
C. 100 meters
D. 3000 meters