Answer:
about 115 women
Explanation:
You need to raise the value on the left side of the ratio by a factor of 100/87. Multiply both numbers by that factor, and you get ...
(100/87)(87) : (100/87)(100)
= 100 : (10,000/87) = 100 : 114.9425...
≈ 100 : 115
There are about 115 women for each 100 men.