months / week / days = calculation

[guy tanguay]

I have a field that give me a total of days, when i do a evaluation (sumerise field)

Ex: 70 days

In the footer

I have a other fields that give me, how many time its gonna take doing this with a "X number of ressouce"

EX: "1" person, then it will be 4.5 months. "2" persons then 2.2 months "3" persons= 1.5 months etc . .

How can i make the calculation smarter by telling me:1 person= 4 months, 2 weeks.

or

2 Persons = 2 months , 1 week

P.S = a Month for me it is 20 days (no working during week-end Yeah

P.s2 = So a week is 5 days

thx, guy