Question 271607
At first glance, it would appear that they would run the second race in a tie.
|__________|Yolanda 100
|_________ |Yoko     90


_|__________|Yolanda 110
 |__________|Yoko    100 



It should also be obvious that they didn't run the race in one hour so that your calculations might be useful to see who ran faster but can't be used for actual distance covered.

What has changed?
Yoko has to run the full 100 yards to win or tie.
Yolanda has to run 110 yards (10 yards more) to win or tie.

But Yolanda is running faster than Yoko.
If Yolanda running 100/90 (10/9) and Yoko is running 90/90 (1) Yolanda will again run 100 yards while Yoko runs 90

So they will be tied at 10 yards before the finish line not at the finish line for the second race.
Which leaves 10 yards each to finish the race.
But we know that Yolanda is running faster than Yoko. How much faster?
For every 100 yards that Yolanda runs Yoko can run 90 so Yolanda runs 10 for every 9 of Yoko. Since they have ten yards to go, Yolanda will win by one yard.