Question 1126950
 Jeff starts driving at 65 miles per hour from the same point that Lauren starts driving at 70 miles per hour. 
 They drive in opposite directions, and Lauren has a half-hour head start.
 How long will they be able to talk on their cell phones that have a 250-mile range? 
:
t = drive time of Jeff
then (half-hour = .5 hrs)
(t+.5) = drive time of Lauren
:
65t + 70(t+.5) = 250
65t + 70t + 35 = 250
135t = 250 - 35
135t = 215
t = 215/135
t = 1.59 hrs is Jeff's travel time
;
Assuming Jeff was talking with Laura during the half hour she alone was driving.
1.59 + .5 = 2.09 hrs which is 2 + .09(60) = 2 hrs 5 min
:
check
1.59(65) + 2.09(70) = 246.65 ~ 250