11/3, 25/7, 18/5. Multiply to find common denominators.
The answer is a because you add the same variables and 5x stays the same

<u>Figure - 1</u> :
Let the missing side as " n "

Therefore the sides will be proportional,
_____________________________
<u>Figure - 2</u> :
Let the missing side as " m "
The Triangles are similar, therefore their sides will be proportional.
_____________________________

Answer: 76 miles per hour
<u>Step-by-step explanation:</u>
east bound: t = 4, r = x - 18
west bound: t = 4, r = x
d = r * t
680 = 4(x - 18 + x)
680 = 4(2x - 18)
170 = 2x - 18
188 = 2x
94 = x
eastbound: x - 18 = 94 - 18 = 76