I know that using the function WEEKNUM you can get the number for a week
through a year

eg. =WEEKNUM(09/29/2008) gets 40

my question is
can it be done backwards??

what i want to do is
type the number of the week (A1)
and get the date of the monday of that week (on B1)

ie
if i type 41
i should get 10/06/2008
(the date of the monday of week 41)