Answer:
20 mph
Step-by-step explanation:
Let speed of Train a = Va mph
Let speed of Train b = Vb mph
Va = Vb + 30
Let time taken for Train a = Ta
Let time taken for Train b = Tb
time taken = distance travelled/speed
Ta = 350/Va = 350/(Vb+30)
Tb = 140/Vb
But they both travel in the same amount of time.
So, Ta = Tb

Cross multiply

Divide both sides by 210

6= - 5/4 (-4) +b
6=-5+b
11=b
y=-5/4+11
22x23=506
hope this helps! good luck!
Is a supposed to be the answer? Is there any other options to choose from the no given list?