A train moving at 60 mph leaves the station at noon. An hour later , a train moving 80 mph leaves heading the same direction on a parallel track. Find the time when the second train catch up to the first.

4 pm

Step-by-step explanation:

We are looking for the time it takes for both trains to travel the same distance.

distance = unknown, but it is the same for both trains

train 1: speed = s = 60 mph, time = t, distance = d

train 2: speed = s = 80 mph, time = t - 1, distance = d

speed = distance/time

distance = speed * time

Train 1:

d = 60t

Train 2:

d = 80(t - 1)

The distances, d, are the same, so

80(t - 1) = 60t

80t - 80 = 60t

20t = 80

t = 4

It takes 4 hours after the first train leaves for the second train to catch up to it, so the second train catches up to the first train at 4 pm.

4 pm

trapezoid

step-by-step explanation:

first i plotted all my points on a grid graph

i made sure all of them were in the correct quadrant

then i saw it was a trapezoid or a quadrilateral

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18