Problema Solution
two boys with two way radios that have a range of 2 miles leave camp and walk in opposite directions. If one boy walks 3mph and the other walks 4mph how long will it take before they lose radio contact?
Answer provided by our tutors
let
v1 = 3 mph the speed of the first boy
v2 = 4 mph the speed of the second boy
d = the distance between the boys
t = the time they need to lose contact
we will use the formula: speed = distance / time
the radios will lose contact when the distance 2 miles that is d = 2 miles.
after t time the distance between the boys is
v1*t + v2*t = d
by substituting the values for v1, v2, and d we find t
3t + 4t = 2
7t = 2
t = 2/7 hours = 2*60/7 min = 17 min 8.6 sec
it takes 2/7 hours = 0.286 hours for the boys to lose radio contact.