Who will win the second race and by how amny seconds?

Question

jack and jill ran a 100 meter race. Jill ran the race in 10 sec and won by 10 meters; that is jack had run 90 meters while jill crossed the finish line. They race again, but this time jill started 10 meters behind the starting line.Who will win the second race and by how amny seconds?

Answer 1

Jill's speed is 100 meters per 10 seconds, or 10 meters per second.

 

Jack ran 90 meters in the same time, so his speed is 9 meters per second.

 

In the second race, Jill has an extra 10 meters to run, so she will have to run 110 meters.  At a speed of 10 meters per second, that means it will take her 11 seconds to run it.

 

Jack just has to run 100 meters.  At 9 meters per second, it will take him 100/9 seconds, or 11 1/9 seconds.

 

So Jill will win the race, by 1/9 second.