The average family in country A spends 60 percent of their disposable income on residence. The average family in country B spends 25 percent of their disposable income on residence. The average monthly salary in country A is $2,500 and in country B is $7,500.

Assume that:

* aside from the difference in income between the families in the 2 countries, the families are identical

* the relationship between the price of residence and the price of other products are identical in the two countries

What is the demand flexibility to residence in relationship to income?