Question

In a town of 6000 people, 1200 are over 50 years old and 2000 are females. If it is known that 30% of the females are over 50 years , what is the probability that a chosen individual from the town is either female or over 50 years?

Answer 1

you need to exclude the overlap first (i.e. females who are over 50).
You can find this by taking 30% of 2000
2000*0.3 = 600

Now add the over 50's, the females, and subtract the overlap and divide by the total population
(1200+2000-600)/6000
2600/6000
26/60
13/30