I believe it would be the first choice
Hope that helps!
55mph.
you can solve it using the equation distance=speed x time
your total distance is 714, and you have 2 trains, one traveling some speed, x, and one traveling x+8, both traveling for 7 hours.
your equation would look like this

and you can then solve for x, which would be 47. this is the speed of the slower train, but 47+8=55 with give you the speed of the faster train.
Answer:
2*square root of 2
Step-by-step explanation:
The square root of 8 is equal to 2*square root of 2