Answer :
5 new houses for every 9 old houses
5 new houses x 9 = 45 new houses
9 old houses x 9 = 81 old houses
answer
81 old houses are there if there are 45 new houses in the city
5 new houses x 9 = 45 new houses
9 old houses x 9 = 81 old houses
answer
81 old houses are there if there are 45 new houses in the city