Probability with different populations and functions

[jackcb]

Homework Statement

In an organsataion employees work either in marketing or sales. 40% are male. 70% of the men work in sales. 60% female. 50% of the women work in marketing.

What is the probability that a randomly selected employee is either male and/or works in marketing?

Homework Equations

The Attempt at a Solution

P(male) = 0.4
P(employee works in marketing) = 0.42
P(male working in marketing) = 0.4 x 0.3 = 0.12

I know it's simple, but I'm very confused now (and stupid!). I would be really grateful if someone could help with this, please?

 

[JFonseka]

It's been a while since I did probability, but I'm pretty sure this is not Calculus, and that question doesn't make much sense to me, I guess I lost touch with basic maths...

 

[Dick]

It may help to think of numbers of employees rather than probabilities. Suppose the total number of employees is N. So the number of male employees is 0.4*N eg. Then if you add the number of females who work in marketing to the total number of males and divide by N, you will have it.

 

[jackcb]

Thank you.

So it there are 100 employees, 40 will be male (of which 12 work in marketing), and there will be 30 women working in marketing too. So I add 40 and 30, getting 70 and the 70/100 = 0.7. Is that right, please?

 

[Dick]

Or just say .4*N are male and .6*.5*N are female and in marketing. Total .7*N. Probability .7*N/N=.7.