Patrick B. answered 06/14/20
Math and computer tutor/teacher
V is Doreen's speed or VELOCITY
Then Sue's speed is V+16
It takes Doreen T hours to travel 49 miles
49 = T * v = Tv
92 = (T-3)* (V+16) = Tv + 16T - 3V - 48
92 = 49 + 16T - 3V - 48 <--- substitutes TV=49
92 = 16 T - 3V + 1
91 = 16 T - 3V
3v + 91 = 16 T
(3v + 91)/16 = t
substitutes this into 49 = T * v = Tv
49 = (3v+91)/16 * v
784 = (3v+91)v
0 = 3v^2 + 91v - 784
0 = (3v + 112)(v-7)
3v+112=0 results in negative measures
v-7=0 ---> v = 7
which forces t=7
Doreen travels 7 mph. She travels for 7 hours, for a distance of 49 miles.
Sue travels 23 mph for 4 hours, which is a distance if 92 miles.
Doreen 7 mph
Sue 23 mph