Two brothers leave from the same point driving in opposite d

Two brothers leave from the same point driving in opposite directions, the first brother driving at 50 miles per hour and the second at 55 mph. The first brother 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? The phones will be out of range hours after the first brother left. (Simplify your answer. Type an integer, fraction, or mixed number.)

Solution

Rate * Tiime = Distance

Let t = time

First Brother is driving 50mph and has one hour head start

= 50(t+1)

Second Brother is driving at 55ph

= 55t

They are going in opposite direction and car phone have 250-mile range.

So 50(t+1) + 55t = 250mph

50t+50+55t = 250

105t = 250-50

t = 200/105

t = 1.9 hours

They will be able to talk 1.9 hours on their phones if they have 250-mile range