Question 373567
one is moving south  2mph
the other west.4mph
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they are moving at right angles from the starting point.
radio range = 2.24 
2.24*2= 4.48 miles is the maximum distance they can be in touch.
let the time in contact be t hours
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south bound distance = 2t miles
weatbound distance = 4t
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(4t)^2+(2t)^2= 4.48^2
16t^2+4t^2=20.0704
20t^2= 20.0704
t^2= 20.0704/20
t^2= 1 hour
t = 1 hour they can be in contact
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m.ananth@hotmail.ca