SOLUTION: Two bicyclists leave the same place traveling in opposite directions. One travels 9 miles per hour and the other travels 6 miles per hour. They have two way radios that will work w

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Question 471493: Two bicyclists leave the same place traveling in opposite directions. One travels 9 miles per hour and the other travels 6 miles per hour. They have two way radios that will work within 5 miles of each other. How long will they be in radio contact?
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
Distance (d) equals Rate (r) times Time (t) or d=rt; r=d/t and t=d/r
Let t=amount of time that they will be in radio contact.
In t hours the first bicyclist travels 9t miles
In t hours the second cyclist travels 6t miles
When these two distances add up to 5 miles, we will have the amount of time that they will be in radio contact, sooooo:
9t + 6t =5
15t=5
t=1/3 hr or 20 min-----------------ans
Another way:
Clearly the two cyclists are separating at the rate of 9+6=15 miles per hour. At this rate, the question is how long will it take them separate a distance of 5 miles???
d=rt; 5=15t
t=20 min
Hope this helps---ptaylor