Answer:
26 minutes 40 seconds past noon.
Alex rides one km
in 1/6 of an hour
Bess rides one km
in 1/9 of an hour
Carey rides
one km in 1/12 of an hour.
Delphine rides one
km in1/15 of an hour.
They ride once
around in 1/18, 1/27, 1/36, and 1/45 of an
hour.
They meet for the
first time in 1/9 of an hour (or 6 2/3
minutes)
Four times in 6 2/3
minutes is 26 2/3
minutes.
