Question

Chi walked 100 meters in 5 minutes. She took another 15 minutes to walk another 400 meters to reach her house. What is her average speed?

Answer 1

Average speed is the ratio of total distance moved by Chi in total time interval

So here we will have

Total distance = 100 m + 400 m

$d = 500 m = 0.5 km$

Total time taken = 5 min + 15 min = 20 min

$T = \frac{20}{60} = \frac{1}{3} hour$

now by the formula of average speed we know that

$v_{avg} = \frac{d}{T}$

$v_{avg} = \frac{0.5 km}{1/3 h}$

$v_{avg} = 1.5 km/h$

so average speed will be 1.5 km/h