SOLUTION: KWAN HIKED UP A HILL AT 4 km AND BACK DOWN AT 6 km HIS TOTAL HIKING TIME IS 3 HRS.HOW LONG DID THE TRIP UPHILL TAKE HIM?

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Question 178070: KWAN HIKED UP A HILL AT 4 km AND BACK DOWN AT 6 km HIS TOTAL HIKING TIME IS 3 HRS.HOW LONG DID THE TRIP UPHILL TAKE HIM?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The distance is the same going up and down
d+=+r%5Bu%5D%2At%5Bu%5D
d+=+r%5Bd%5D%2At%5Bd%5D
given:
r%5Bu%5D+=+4km/hr
r%5Bd%5D+=+6km/hr
t%5Bu%5D+%2B+t%5Bd%5D+=+3hrs
d+=+4%2At%5Bu%5D
d+=+6%2At%5Bd%5D
I can set the right sides equal to eachother
4%2At%5Bu%5D+=+6%2At%5Bd%5D
t%5Bu%5D+=+%283%2F2%29%2At%5Bd%5D
And, since
t%5Bu%5D+%2B+t%5Bd%5D+=+3
%283%2F2%29%2At%5Bd%5D+%2B+t%5Bd%5D+=+3
3t%5Bd%5D+%2B+2t%5Bd%5D+=+6
5t%5Bd%5D+=+6
t%5Bd%5D+=+6%2F5hrs
and
t%5Bu%5D+=+%283%2F2%29%2At%5Bd%5D
t%5Bu%5D+=+%283%2F2%29%2A%286%2F5%29
t%5Bu%5D+=+9%2F5hrs
The uphill trip took 1 hr and 4/5 of an hr, or
1 hr and 48 minutes
check:
d+=+r%5Bu%5D%2At%5Bu%5D
d+=+4%2A%289%2F5%29
d+=+36%2F5
------------------
d+=+r%5Bd%5D%2At%5Bd%5D
d+=+6%2A%286%2F5%29
d+=+36%2F5
The distances are equal as they should be, and
6%2F5+%2B+9%2F5+=+3, the total time is 3 hrs