Question

In a library where the ratio of men to women is 1 to 1, _____ of the total members are men.

Answer 1

%50, because if the total equals to 100, 1/2 of that is 50

Answer 2

If a ratio is 1:1, for every man in the room is a women. This will mean there will always be half of the total members that are men.
Half fills in the blank.
There are many ways to express half, such as 50%, (1/2), .5, 1:2, etc