Answer: they would be able to talk to each other for 1.5 hours
Step-by-step explanation:
If each brother has a communication device that allows him to talk to the other for up to a 210-mile range, by the time they are 210 miles apart, they won't be able to communicate to each other. This means that they would have travelled a total distance of 210 miles.
Let t represent the time it takes either brothers to travel his own distance.
the first brother driving at 55 miles per hour. If the first brother has a one-hour head start, this means that the time spent by the first brother is (t + 1) hour.
Distance = speed × time
Distance travelled by the first brother is
55(t + 1) = 55t + 55
The second brother was driving at 55 miles per hour. This means that distance travelled by the second brother in t hours is
50t
Since the total distance covered is 210 miles, then
55t + 55 + 50t = 210
105t = 210 - 55 = 155
t = 155/105 = 1.476 hours
Approximately 1.5 hours
