Answer: 140 female runners
Step-by-step explanation:
First find out the number of runners:
= 42% * 10,000
= 4,200 runners
Then find out the number of female runners:
= 4,200 * 1/3
= 1,400 female runners
Sally finished faster than 90% of the female runners which means that 10% finished faster or at the same time as her.
= 10% * 1,400
= 140 female runners