Going from 5 work days to 4 is a 20% cut in work/pay and a 50% increase in weekends (2 to 3). 4 to 3 is a 25% cut and a 33% increase in weekends (3 to 4). 3 t

Going from 5 work days to 4 is a 20% cut in work/pay and a 50% increase in weekends (2 to 3). 4 to 3 is a 25% cut and a 33% increase in weekends (3 to 4). 3 to 2 is a 33% cut and a 25% increase in weekends (4 to 5). Thus we see, 3 work days a week is mathematically optimal.