David's family rented a boat for a flat fee of $20 plus an hourly, X. David's family rented the boat for 4 hours. The equation 4x + 20 = 60 represents, in dollars, what David's family paid for renting the boat. What is the hourly rate for renting the boat?

$10

Step-by-step explanation:

4x + 20 = 60

-20 from each side

4x = 40

divide each side by 4

x = 10

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."