Question 437499
We can let {{{a[m]}}} and {{{a[w]}}} be the number of adult men and women, and let {{{(7/8)(a[m]) = (2/3)(a[w])}}}. This process definitely works, but a much faster way is to assign specific numbers of men and women since we only care about the ratio between the married people and the population.


Suppose that there are 80 males in the town (you can claim this "without loss of generality," a famous expression used in math). Then, 70 of them are married to 70 different women. 70 is 2/3 of 105, so there are 195 people in the town. 70 males and 70 females are married, so the ratio of married individuals to the entire population is 140/195 = 28/39.