Question

Please help me with this question guys.

Answer 1

The average speed is 22.2 km/h

Step-by-step explanation:

Average Speed

Given an object travels a total distance d and took a total time t, then the average speed is:

`\displaystyle \bar v=(d)/(t)`

The mailman first drives d1=7 km at v1=15 km/h. The time taken to drive is:

`\displaystyle t1=(d1)/(v1)=(7)/(15)=0.467\ h`

Then he drives d2=7 km at v2=43 km/h taking a time of:

`\displaystyle t2=(d2)/(v2)=(7)/(43)=0.163\ h`

The total time is

t=0.467 h + 0.163 h = 0.63 h

The total distance is

d = 7 km + 7 km = 14 km

The average speed is:

`\displaystyle \bar v=(14)/(0.63)=22.2\ km/h`

The average speed is 22.2 km/h