Probability question--Confusing

[dddanny2006]

In a certain corporation, there are 300 male employees and 100 female employees. It is known that 20% of the male employees have advanced degrees and 40% of the females have advanced degrees. If one of the 400 employees is chosen at random, what is the probability this employee has an advanced degree and is female?

A)1/20
B)1/10
C)1/5
D)2/5
E)3/4

ANSWER-B Source-Magoosh

I did it this way- P(Advanced degree) AND P(Female)
(100/400)*(100/400) =1/16

I have not been able to apply the Manhattan Concepts in this problem.Im finding probability difficult,please advice on going about it.

Thanks

[RonPurewal]

If you have a set total, then "probability questions" aren't really even probability questions.
You know there are 400 people here, so there's no sense in even thinking about probability rules. If you can just find the number of people you want, then you can divide it by 400 and you're done.

Here, there are 100 women, 40% of whom have degrees, so there are 40 women with degrees.
So, 40/400.

"Probability rules" are only a thing when you don't have a fixed total. If you have a fixed total, then just use normal numbers.