The answer is: " 9 mi. "
_____________________________________________
Note:
_____________________________________________
1 week = 7 days
Total exercise: 30 mi/ wk.
3 mi * 7 = 21 mi. / wk running.
How many miles per week biking?
Assuming that her exercise is strictly: 1) running; and 2) biking:
30 mi - 21 mi. = 9 mi.
_____________________________________________
The answer is: " 9 mi. "
_____________________________________________
