The distance between two cities is 330km. two cars leave the two cities at the same time and drive towards each other with speeds of 85km/hr and 80km/hr. after how many hours will the cars meet? if x is the time of the hours, model the problem with the correct equation

Multiply the speed of each car by x ( time) and add them together to equal total distance.

85x + 80x = 330

Simplify:

165x = 330

Divide both sides by 165:

x = 330 / 165

x = 2

Check:

85 x 2 =170

80 x 2 = 160

170 + 160 = 330

It takes 2 hours.

- "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."