Question 112834
Ellen and Kate raced on their bike to the library after school. They both left school at 3p.m. and biked along the same path. Ellen rode at a speed of 12 mph and Kate rode at a speed of 9 mph. Ellen got to the library 15 minutes before Kate. How long did it take Ellen to get to the library and what time did Ellen get to the library.
:
Let t = time required (in hrs) for E to get to the library
Then
(t + .25) = time required for K to get to the library (changed 15 min to hrs)
:
We know they both traveled the same distance. Make a distance equation
Dist = speed * time
:
E's dist = K's dist
12t = 9(t + .25)
12t = 9t + 2.25
12t - 9t = 2.25
3t = 2.25
t = 2.25/3
t = .75 hr or 45 min
:
E got to the library at 3:45
:
:
Confirm out solution by finding that they did, in fact, travel the same distance
K's time .75 + .25 = 1 hr
9 * 1 = 9 mi
12 * .75 = 9 mi
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Did this make sense to you? Any questions?