Question

Michael was driving at a constant speed of 60 mph when he crossed the Sandy River. After one hour he passed a highway marker for mile 84 right now equation in point slope form, and find which highway markers your past 90 minutes after crossing the Sandy River.

I know the answer but need help with the work please explain.

Answer 1

Mile marker 114

Explanation:

Our slope is 60 mph

Let x be the time in hours and y be the miles

Our point is (1 ,84)

We have a point and a slope

We can use point slope form to find the equation

y-y1 = m(x-x1)

y-84 = 60(x-1)

We want to find y when the time is 90 minutes

We need to change 90 to hours

90 minutes * 1 hour/60 minutes = 1.5 hours

Substitute this into the equation to find the miles, which is the mile marker

y - 84 = 60 (1.5 -1)

y - 84 = 60(.5)

y -84 = 30

Add 84 to each side

y-84+84 = 30+84

y = 114

You should pass mile marker 114