Alice cycles to Carla's house at 12 miles per hour and returns by car at 36 miles per hour. If the round trip took 1 hour, how far from Carla does Alice live?
+128475 Let the time she travels at 12 mph = x minutes and if she trqvels back at 36 mph.....since this is 3 times as fast...it must take her x / 3 minutes to return
So
x + x/3 = 60 mutiply through by 3
3x + x = 180
4x = 180 divide by 4
45 = x
So....she travels 45/3 minutes = 15 minutes at 36 mph
And since 15 minutes = 1/4 hr......the distance is
Rate x Time = 36mph x 1/4 hr = 9 miles
