Question

A train travels 120 km at a speed of 60 km/h, makes a stop for 0.5 h, and then travels the next 180 km at a speed of 90 km/h. What is the average speed of the train for this trip? 9th grade level pls FFFFFFFFFFFAAAAAAAAAAASSSSSSSSSSSSSTTTTTTTTTTTTT

Answer 1

average speed = 66.67 km/h

Step-by-step explanation:

In order to find the average speed of the train, you need to calculate the total distance traveled, divided by the time it took to cover that distance. So for the total distance:

Distance= 120 km + 180 km = 300 km

For the total time we need to add three different quantities, two of which we need to derived based on the information provided:

time for first part of the trip:

`time_1=(D_1)/(v_1) =(120)/(60) \,h= 2\,h`

for the time of the stop:

`time_2=0.5\,\,h`

for the last part of the trip:

`time_3=(180)/(90) \,h= 2 \,\,h`

Which gives a total of 4.5 hours

Then, the average speed is: 300/4.5 km/h = 66.67 km/h