Question

Please help me with this question guys.

Answer 1

Answer:

The average speed is 22.2 km/h

Explanation:

Average Speed

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

$\displaystyle \bar v=\frac{d}{t}$

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

$\displaystyle t1=\frac{d1}{v1}=\frac{7}{15}=0.467\ h$

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

$\displaystyle t2=\frac{d2}{v2}=\frac{7}{43}=0.163\ h$

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:

$\displaystyle \bar v=\frac{14}{0.63}=22.2\ km/h$

The average speed is 22.2 km/h