SOLUTION: Alan and Dave Schaferkotter leave from the same point driving in opposite directions, Alan driving at 55 miles per hour and Dave at 65mph. Alan has a one-hour head start. How long

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Question 157346This question is from textbook Beginning Algebra
: Alan and Dave Schaferkotter leave from the same point driving in opposite directions, Alan driving at 55 miles per hour and Dave at 65mph. Alan has a one-hour head start. How long will they be able to talk on their car phones if the phones have a 250-mile range? This question is from textbook Beginning Algebra

Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
Remember:
Speed=distance%2Ftime -------------> working eqn
Alan=A=55m%2Fhr, speed of Alan
Dave=D=65m%2Fhr, speed of Dave
We have to remember Alan has a head start of 1 hour & travelled a certain distance and lets' see how far he is:
A%5B1%5D=%2855m%2Fhr%29%281cross%28hr%29%29=55miles
IN our working eqn we get: time=distance%2Fspeed
The distance will be the max range = 250 miles but we need to deduct A%5B1%5D because we'll take the speed for both.
In just make sense to deduct because that 55 miles run, Dave was not part of it.
t=d%2Fs
t=%28250-55%29cross%28m%29%2F%28%2855%2B65%29%28cross%28m%29%2Fhr%29%29
t=%28195%2F120%29hr
t=1.625hr= 1 hour & 37.5 minutes ------------------> This long they can talk on their car phones. FINAL ANSWER
In doubt? Go back working eqn we get, d=%28speed%29%28time%29
this time we have to add A%5B1%5D because the time we'll use we deduct it. We take speed for both and d=max range.
d=%2855%2B65%29%28m%2Fcross%28hr%29%29%281.625cross%28hr%29%29%2B55m
250m=195m%2B55m
250m=250m
Thank you.
Jojo