One way to do this is to notice

Then

We have

and since
has a period of
,

and so

Answer:
Step-by-step explanation:
D
Answer:
11 km/hr.
Step-by-step explanation:
Given information:
Simulated speed = 20/km/h
Time = 15 mins = 1/4 hr = 0.25 hr
Distance Covered as per simulated speed = 
Position of Julian according to the app =
.
Actual distance covered by the bike is

Formula for speed:



Therefore, the average speed of Julian is 11 km/hr.