Answer:Lilah's speed on the train is 60 mph and Mason's speed is 75 mph
Explanation:
Let x represent the speed of Lilah.
Lilah is moving from Portland to Seattle. It takes her 3 hours to go by train.
Distance = speed × time
Distance covered by Lilah in moving from Portland to Seattle would be
3 × x = 3x
It takes him 2.4 hours to get to Seattle, driving at 15 miles per hour faster than the speed of the train.
It means that Mason's speed is
x + 15
Distance covered by Mason would be
2.4(x + 15) = 2.4x + 36
Since the distance from Portland to Seattle is the same, then
3x = 2.4x + 36
3x - 2.4x = 36
0.6x = 36 x = 36/0.6 = 60 mph
Mason's speed would be 60 + 15 = 75 mph