Cpt question 2012

Proprietor used a rented building both for
business purpose and as well as residence
equally. The rent paid during the year for the
building was Rs.1,32,000 debited to rent
expenses A/c in the books of business. One
month rent is still outstanding. Liability of the
business for rent outstanding

Given Rent paid for one year for both business and residence and also given one month rent outstanding

therefore 132000/11=11000.

11000/2=5500

but answer is 6000 why ?