A boat travels upstream a distance of 24 miles on a river whose current is a constant rate of 3 mph. The boat returns downstream. The trip up the
river and back down the river takes a total time of 6 hours. What would the speed of the boat
be in still water?

d

step-by-step explanation:

the two points from this line are   (0,4)   & (2,-2)

we can call

now, lets find the slope (m):

now finding b (the y intercept). this is the point at the y-axis where the line cuts the axis. looking at the graph, it is y = 4. so the point is 4. hence b = 4

the slope-intercept form is given by  

putting the points, we have:

d is the correct answer.

$11.60 is your answer but this is in us dollars