Question

Year8 maths(speed)

Anna rode her bike to school one morning, a distance of 15 km, at an average speed of 20 km/h. It was raining in the afternoon, so Anna decided to take the bus home. The bus trip home took 30 minutes. What was Anna’s average speed for the return journey to and from school?

Could you write how to solve this question?

Answer 1

Step-by-step explanation:

While moving towards school=>

distance (d1) = 15km

speed (S1)= 20km/hr

time taken = (d1)/speed = 15/20 = 0.75hr

while moving back from school=>

time = 30min = 1/2hr = 0.5 hr

distance (d2) = 15km

speed (S2) = (d2)/time = 15/0.5 = 30km/hr

Avg. speed = total distance/total time

=> (15+15)/(0.75+0.5)

=>30/1.25 = 24km/hr