Answer
In 2010, there were approximately 5,549 people in the Coast Guard who were women.
Work Step by Step
We are told that in 2010, 13.1 out of every 100 people in the Coast Guard were women, and we want to approximate the total number of people in the Coast Guard who were women given that there were 42,358 total people in the Coast Guard.
So let $x$ be the total number of women in the Coast Guard.
Then we must have $$\dfrac{x}{42,358}=\dfrac{13.1}{100}.$$
We first cross multiply, then solve for $x$:
$$100x=554889.8 \\ x=5548.898.$$
Since we can't have a fraction of a person, we round our value to the nearest whole number, which is 5549.
So in 2010, there were approximately 5,549 people in the Coast Guard who were women.
