Question 798511
3 persons consuming the sack in 36 days would be same as a one person rate of 1 person in 3*36 days.  This is {{{1/(3*36)}}} sacks per day, or {{{1/108}}} sacks per day.


The rate then for 9 persons is {{{9(1/108)=1/12}}} sacks per day.
This means 12 days for these 9 persons.