SOLUTION: Gerry and Tony live 11km apart. Gerry leaves his home at 2 p.m. and bikes toward Tony's home at 25 km/hr. At the same time, Tony leaves his home and bikes toward Gerry's home at 30

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Question 175901This question is from textbook algebra 1
: Gerry and Tony live 11km apart. Gerry leaves his home at 2 p.m. and bikes toward Tony's home at 25 km/hr. At the same time, Tony leaves his home and bikes toward Gerry's home at 30 km/hr as soon as they reach each other's homes they turn around and start back along the same route. They stop when they meet each other on the ride back to their own homes. How far are they are from Gerry's home when they stop? This question is from textbook algebra 1

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
For both,
d+=+r%2At
Each has their own rates, times and distances, so
d%5Bt%5D+=+r%5Bt%5D%2At%5Bt%5D Tony's equation
d%5Bg%5D+=+r%5Bg%5D%2At%5Bg%5D Gerry's equation
Each bikes to the others house and they leave at the same time, so
For Tony,
d%5Bt%5D+=+r%5Bt%5D%2At%5Bt%5D
11+=+30%2At%5Bt%5D
t%5Bt%5D+=+11%2F30hrs
and, for Gerry,
d%5Bg%5D+=+r%5Bg%5D%2At%5Bg%5D
11+=+25%2At%5Bg%5D
t%5Bg%5D+=+11%2F25hr
Comparing these, with LCD
t%5Bt%5D+=+55%2F150
t%5Bg%5D+=+66%2F150
So, Tony got to Gerry's house 11%2F150hrs quicker
than Gerry got to Tony's house.
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Now, they turn around and head back toward eachother.
If they left at the exact same time, the elapsed
time for each until they met would be the same
t%5Bt%5D+=+t%5Bg%5D, but Tony gets a head start.
-------------------
Assume I have a stopwatch and I'm in a helicopter overhead
so I can see both of them. I'll start the stopwatch when
Gerry turns around 11%2F150 hr after Tony has turned around.
If Gerry's time to where they meet from Tony's house is t%5Bg%5D
then Tony's time from Gerry's house is t%5Bg%5D+%2B+%2811%2F150%29
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Now my equations are
d%5Bt%5D+%2B+d%5Bg%5D+=+11km
d%5Bt%5D+=+11+-+d%5Bg%5D
where these are the distances each travel to where they meet
(1) d%5Bt%5D+=+30%2A%28t%5Bg%5D+%2B+%2811%2F150%29%29
(2) d%5Bg%5D+=+25t%5Bg%5D
rewriting (1)
(1) 11+-+d%5Bg%5D+=+30%2A%28t%5Bg%5D+%2B+%2811%2F150%29%29
Substitute (2) in (1)
11+-+25t%5Bg%5D+=+30t%5Bg%5D+%2B+30%2A%2811%2F150%29
55t%5Bg%5D+=+11+-+11%2F5
275t%5Bg%5D+=+55+-+11
t%5Bg%5D+=+44%2F275hr
t%5Bg%5D+=+.16hrs or 9.6 min
------------------
The distance Tony travels is the distance from Gerry's
house when they meet
(1) d%5Bt%5D+=+30%2A%28t%5Bg%5D+%2B+%2811%2F150%29%29
d%5Bt%5D+=+30%2A%28.160+%2B+.0733%29
d%5Bt%5D+=+30%2A.2333
d%5Bt%5D+=+7km
They meet 7 km from Gerry's house
check answer:
(2) d%5Bg%5D+=+25t%5Bg%5D
d%5Bg%5D+=+25%2A.16
d%5Bg%5D+=+4
and
d%5Bt%5D+%2B+d%5Bg%5D+=+11km
7+%2B+4+=+11
OK