Respuesta :
Answer : The average speed of cyclist B is 25.714 km/hr
Explanation :
First we have to convert average speed from km/hr to m/s.
Conversion used : [tex]km/hr=\frac{5}{18}m/s[/tex]
As we are given the average speed of cyclist A 20 km/hr. The average speed in m/s is:
As, [tex]1km/hr=\frac{5}{18}m/s[/tex]
So, [tex]20km/hr=20\times \frac{5}{18}m/s=5.555m/s[/tex]
Now we have to calculate the time taken by cyclist A to travel the distance.
[tex]Speed=\frac{Distance}{Time}[/tex]
[tex]5.555m/s=\frac{30000m}{Time}[/tex]
[tex]Time=\frac{30000m}{5.555m/s}[/tex]
[tex]Time=5400s[/tex]
conversion used : (1 min = 60 sec)
[tex]Time=\frac{5400}{60}=90min[/tex]
As per question, cyclist B travels same distance in same time but he took rest for 20 min. That means,
Time taken by cyclist B = 90 min - 20 min = 70 min
Now we have to calculate the average speed of cyclist B.
[tex]Speed=\frac{Distance}{Time}[/tex]
[tex]Speed=\frac{30km}{70min}[/tex]
[tex]Speed=\frac{30km}{(\frac{70}{60}hr)}[/tex]
conversion used : (1 hr = 60 min)
[tex]Speed=25.714km/hr[/tex]
Therefore, the average speed of cyclist B is 25.714 km/hr
