posted by scooby doo .
lois rode her bike to visit a friend. She traveled at 10 miles an hour. While she was there it began to rain. Her friend drove her home at 25 miles per hour. Lois took 1.5 hours longer to go to a friends then to return home. How many hours did it take Lois to arrive at her friend's house?
distance = rate x time.
return trip = 25 mph x time
going = 10 mph x (time + 1.5)
distance is the same; therefore, set them equal to each other.
25t = (10(t+1.5)
solve for time
time + 1.5 = time it took Lois to go to her friends house. Post your work if you get stuck.
Call the two times t1 and t2. Call the distance between points D.
D = 10 t1
D = 25 t2
t1 = t2 + 1.5
t1 = 2.5 t2 would be a good substitution in the last equation. Then you will have one equation on one unknown (t2). Once you have that, you can compute t1.