Math

posted by David

Carrie and Crystal live at a equal distances from school. Carries walks to school at an average rate of 3 miles per hour and Crystal rides her bike at an avergae rate of 9 miles per hour. It takes Carrie 20 minutes longer than Crystal to get to school. How far do Crystal and Carrie live?

1. bobpursley

distanceCarrie=3mi/hr*time
distanceCrystal=9mi/hr*(time-1/3) 20 min is 1/3 of an hr...

set them equal

3t=9t-3
t= 1/2 hr

now you can figure the distance from the first equation.

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