Answer:
Every 60 days.
Step-by-step explanation:
This is very similar to a sequence.
try starting out with:
Abe: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21
Barb: 2, 4, 6, 8, 10
Carl: 3, 6, 9, 12
Dee: 4,8, 12, 16, 20, 24, 28, 32, 36
Earl: 5, 10, ....
so If today they all worked together....
We need a common multiple of 5, 4, 3.... so it is 60
It appears that it will be in 60 days
