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:
x=3
Step-by-step explanation:
Answer:
y = mx + c
m = -4
at y intercept x = 0
(x,y) =(0,-3)
-3 = -4(0) + c
c = -3
therefore the answer is y = -4x + c
Answer:
12.5%
Step-by-step explanation:
The price increased from 800 to 900. So what is the PERCENTAGE INCREASE??
The increase is 900 - 800 = 100
To find this in terms of original, we need to divide 100 by 800 and multiply by 100 to get the "percentage". Let's do it:

So the increase is 12.5% and thus the general sales tax is 12.5%
Divide everything by 8: 550/8=68.75, 250/8=31.25. The new dimensions are 68.75 inches by 31.25 inches :)