Depends on how much she's in shape.
I would say between 10 and 11 minutes
A 28 year old female should be able to run a mile in about 7 minutes. Therefore, a three mile run should take about 21 minutes.
Much depends on the condition and experience of the runner. On average, a mile will take anywhere from 10 and 12 minutes for a person in reasonably good health to run.
Depends how fit they are but any thing around 14 minutes =D
An average time for running a mile for any ten-twelve year olds is around 7-9 minutes.
Its about 6:15