SOLUTION: A bike trail is 21 miles long. If a biker travels 8mph for the first of the trail and 12 mph for the second part, how far did the biker travel at the slower speed if he traveled f

Question 833622: A bike trail is 21 miles long. If a biker travels 8mph for the first of the trail and 12 mph for the second part, how far did the biker travel at the slower speed if he traveled for a total of two hours
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A bike trail is 21 miles long.
If a biker travels 8mph for the first of the trail and 12 mph for the second part, how far did the biker travel at the slower speed if he traveled for a total of two hours?
:
Let t = time traveled at 8 mph
then
(2-t) = time traveled at 12 mph
:
Write a distance equation; dist = 2peed * time
:
Slow dist + fast dist = 21 mi
8t + 12(2-t) = 21
8t + 24 - 12t = 21
8t - 12t = 21 - 24
-4t = -3
t = -3/-4
t = 3/4 of an hr at the slow speed
:
;
Check this out, find the dist at each speed, using decimal hrs
8*.75 = 6 mi
12*1.25 = 15 mi
------------------
total d: 21 mi
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