Question 54452
I am not sure what the "six-step method" is, but I would set it up using the distance formula: distance = (rate)(time)
.
Train A: distance (A)=(65mph)(time)
Train B: distance (B)=(75mph)(time)
.
Train A + Train B = 280 miles, than 
65t + 75t = 280
140t=280
t=280/140
t=2 hours before they are 280 miles apart.
.
Check by plugging (t=2) back into each equation.
Train A: distance (A)=(65mph)(2)=130 miles
Train B: distance (B)=(75mph)(2)=150 miles

130 miles + 150 miles = 280 total miles