Answer:
Total time taken by walking, running and cycling = 22 minutes.
Step-by-step explanation:
Let the speed of walking = x
As given,
The distance of walking = 1
Now,
As 
⇒ Time traveled by walking = 
Now,
Given that - He runs twice as fast as he walks
⇒Speed of running = 2x
Also given distance traveled by running = 1
Time traveled by running = 
Now,
Given that - he cycles one and a half times as fast as he runs.
⇒Speed of cycling =
(2x) = 3x
Also given distance traveled by cycling = 1
Time traveled by cycling = 
Now,
Total time traveled = Time traveled by walking + running + cycling
=
+
+ 
= 
If he cycled the three mile , then total time taken =
+
+
= x
Given,
He takes ten minutes longer than he would do if he cycled the three miles
⇒x + 10 = 
⇒
⇒
⇒x =
= 12
⇒x = 12
∴ we get
Total time traveled by walking + running + cycling =
min