Mary ran for 3 1/2 h at a speed of 7km/h. She then ran a distance of 12 1/2 km. She took 6 hrs altogether.Find her running average speed.

Question

Pls ans asap.

Answer 1

To find the average speed, you want to find the total distance and divide it by the total time.  They give you information about two sections of the run that allows you figure this out.

 

1. During the first part of the run, she ran 3.5 hours at a speed of 7 km/h.  To find the the distance she ran, multiply the speed times the time:  3.5 x 7 = 24.5 km.

 

2. During the second part of the run, she ran 12.5 km.

 

So the total distance she ran is 24.5 + 12.5 = 37 km.

 

They tell you that the total time was 6 hours.

 

So you have everything you need.  Divide 37 by 6 to get the average speed, which comes to 6 1/6 km/h.