For the sake of completion:
Suppose there are N employees.
76% = 0.76N are men; 24% = 0.24N are women.
Suppose also that n men being underpaid for their work.
The stat as quoted suggests there are n women being underpaid. (Or, sufficiently close to n, that a stronger stat can't be quoted)
Chance of men being underpaid: n/0.76N
Chance of women being underpaid: n/0.24N
Chance of women being underpaid is therefore (n/0.24N)/(n/0.76N) = 19/6 > 3.1 times higher.
I rounded conservatively to conclude "women are three times more likely to be underpaid".