Answer:
90 minutes or 1.30 hours
Step-by-step explanation:
In 72 minutes, Sue ran 12 miles per hour
In 1 minute, Sue ran 12/72 miles per hour
In 60 minutes, Sue ran (12/72)*60 miles per hour
= 10 miles per hour
Remaining miles after completing 12 miles in 72 minutes = (24-12) = 12 miles.
If the mileage decreases to 2 miles per hour, he will now run = (10 - 2) = 8 miles per hour.
Now,
1 hour = 60 minutes
Sue can run 8 miles in 60 minutes
Sue can run 1 miles in 60/8 minutes
Sue can run 12 miles in (60/8)*12 minutes
= 90 minutes or 1.30 hours