10 miles - 3 miles = 7 miles left.
1 hour 20 minutes - 24.7 minutes= 80 minutes - 24.7 minutes
= 55.3 minutes left
Therefore, you have 55.3 minutes left to run 7 miles. But since you want to finish in LESS than 1 hour and 20 minutes, subtract the .3.
So:
7 miles = 55 minutes
1 mile x minutes
x minutes= 55 x 1 ÷ 7 miles
x minutes = 7.85
x minutes = ~ 8 minutes
Therefore you have to run every mile in ~ 8 minutes.
Hope this helps!
