To find the ratio of male income to female income, we simply divide the average income of Australian males by the average income of Australian females.
Ratio of male income to female income = Average income of Australian males / Average income of Australian females
Ratio of male income to female income = $60,000 / $40,000
Simplifying the ratio by dividing both the numerator and denominator by the greatest common divisor (GCD), we get:
Ratio of male income to female income = 3/2
Therefore, the ratio of male income to female income, in lowest terms, is 3:2