
Answer:
17.32 seconds
Step-by-step explanation:
To solve this problem we need to the instances given:
 Number of friends  = 4;
 Distance covered  = 100yards
Now, sentence by sentence;
 Jason ran the race = 17.32 seconds
Bill ran the race 1.78 seconds faster than Jason;
 Bill's time = 17.32 + 1.78  = 19.1 seconds
Bill's time was 0.84 seconds more than Art's;
  Art's time  = 19.1 + 0.84  = 19.94 seconds
Pablo's time was 1.23 seconds less than Bill's,
  Pablo's time  = 19.1 - 1.23  = 17.87 seconds
The winning would be that of the friend with the lowest time, the lower the time higher the speed.
So Jason's time is the winning time = Â 17.32 seconds