SOLUTION: if two friends leave from the same place traveling to a destination of 720 miles away, and one leaves 2 hours before the other traveling at a rate of 60 miles an hour and the other

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: if two friends leave from the same place traveling to a destination of 720 miles away, and one leaves 2 hours before the other traveling at a rate of 60 miles an hour and the other      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 143652: if two friends leave from the same place traveling to a destination of 720 miles away, and one leaves 2 hours before the other traveling at a rate of 60 miles an hour and the other leaves traveling at a rate of 80 miles an hour, at what time would they pass eachother on the road?
Found 2 solutions by josmiceli, ankor@dixie-net.com:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Imagine you have a stopwatch. Start the stopwatch the instant
the 2nd friend leaves. Then ask: "where is the 1st one at that time?"
He has gone 60%2A2+=+120mi
When will they pass eachother?
Call the distance the 1st one has to go d
Then the distance the 2nd one has to go will be d+%2B+120
The stopwatch will show the same time for both when they meet
d%2Ft+=+60 for 1st friend
%28d+%2B+120%29%2Ft+=+80 for 2nd friend
-------------------------------------
d%2Ft+=+60
d+=+60t
%2860t+%2B+120%29%2Ft+=+80
60t+%2B+120+=+80t
20t+=+120
t+=+6hrs
They will meet in 6 hours
check:
d%2Ft+=+60
d%2F6+=+120
d+=+720
%2860t+%2B+120%29%2Ft+=+80
%2860%2A6+%2B+120%29%2F6+=+80
360+%2B+120+=+480
480+=+480
OK

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
if two friends leave from the same place traveling to a destination of 720 miles away, and one leaves 2 hours before the other traveling at a rate of 60 miles an hour and the other leaves traveling at a rate of 80 miles an hour, at what time would they pass each other on the road?
:
The destination distance is irrelevant, as long as it is greater than the
distance where one passes the other
:
Let t = travel time of the 1st person
then
(t-2) = travel time of the 2nd person
:
We know when 1 passes the other, they will have traveled the same distance
Write a distance equation: Dist speed * time
:
2nd person dist = 1st person dist
80(t-2) = 60t
:
80t - 160 = 60t
;
80t - 60t = +160
:
20t = 160
t = 160%2F20
t = 8 hrs from the time the 1st person starts or 6 hrs after the 2nd person starts:
:
Check by finding the distances:
60*8 = 480
80*6 = 480