Final answer:
To solve the problem, the number of women in the hall can be represented by 'w'. After one-third of the men and 436 of the women left, the number of men remaining is (2/3)(w + 624) and the number of women remaining is (w - 436). Setting up an equation and solving for 'w' gives the answer of 780 women in the hall at first.
Step-by-step explanation:
To solve this problem, let's use algebraic expressions. Let the number of women in the hall be represented by 'w'. The number of men would then be 'w + 624'.
After one-third of the men and 436 of the women left, the number of men remaining would be (2/3)(w + 624) and the number of women remaining would be (w - 436).
According to the given information, (3/5) of the remaining people in the hall were men. So we can write the following equation:
(2/3)(w + 624) = (3/5)[(2/3)(w + 624) + (w - 436)]
Simplifying and solving for 'w', we get:
w = 780
Therefore, there were 780 women in the hall at first.