Train A's speed = x
Train B's speed = x + 10
4.5(x + x + 10) = 432
Distribute both sides by 4.5
x + x + 10 = 96
Combine like terms.
2x + 10 = 96
Subtract 10 from both sides.
2x = 86
Divide both sides by 2
x = 43
Train A = x = 43 mph
Train B = x + 10 = 43 + 10 = 53 mph