A
farmer owns a cow, a goat and a goose.
She
decides to go on
holidays.
She
must insure that the
grass field can feed her three animals during her absence.
Information:

The cow eats as much
grass as the goat and the goose.

The grass field can
feed the cow and goat for 45 days.
 The grass field
can feed the cow and goose for 60 days.
 The grass field can feed
the goose and
goat for 90 days.
Question:
How many days can
she leave before her three animals run out of grass?
Answer
: 36 days
(Prove the answer..:)
