Question 148949
She averaged 75 mph along the route from Albuquerque to Roswell and averaged 70 mph from Roswell to Carlsbad. She covered the entire 220 miles in 3 hours. How long did she take to drive from Albuquerque to Roswell?
:
Let t = time to go from Al to Ros
Then
(3-t) = time to go from Ros to Car
:
Write a dist equation: Dist = speed * time
:
A>R dist + R>C dist = 220 miles
75t + 70(3-t) = 220
;
75t + 210 - 70t = 220
:
75t - 70t = 220 - 210
:
5t = 10
t = {{{10/5}}}
t = 2 hrs from Al to Ros
:
:
Check solution by finding the total distance: (3-2 = 1 hr Ros to Car)
75*2 + 70*1 =
150  + 70 = 220