To do this you have to divide 135 miles by 5 hours. You will get the answer of 27 miles per hour.
6x - 4y = 30
-4y = -6x + 30
y = 3/2x - 15/2....slope here is 3/2. A perpendicular line will have a negative reciprocal slope. All that means is flip the slope and change the sign. So ur perpendicular line will have a slope of -2/3 (see how I flipped 3/2 making it 2/3...and then changed the sign, making it -2/3)
answer : perpendicular line will have a slope of -2/3.
Y=3x + 8.25
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3/4 is 75% so the answer is 75% out of 100
Hope that helps!:)