The population of house1 and house2 is 5 and 7 respectively.

If one person from house1 goes to house2, then the population of house2 is twice the population of house1.

5 and 7

5-1 and 7+1

4 and 8

While if one person from house2 goes to house1, then the population of house2 is same as the population of house1.

5 and 7

5 +1 and 7 -1

6 and 6