Answer: 0.474 miles
Step-by-step explanation:
First find out how fast they can run per minute.
Phil runs 3/8 miles in 7 minutes:
Speed = Distance / Time
= 3/8 ÷ 7
= 0.0536 miles/minute
Joe runs 5/8 miles in 9 minutes:
Speed = 5/8 ÷ 9
= 0.0694 miles per minute
In 30 minutes, Phil will run:
= Miles per minute * Time
= 0.0536 * 7
= 1.608 miles
Joe will run:
= 0.0694 * 30
= 2.082 miles
Difference:
= 2.082 - 1.608
= 0.474 miles