# Statistics, probability help!

1. Jul 6, 2011

### Calculator14

1. The problem statement, all variables and given/known data

The probability of Mr. Jones being selected for jury duty is 70%. The probability that Mr. Smith will be selected is 40%. The probability that neither will be selected is 10%. What is the probability that both are selected?

2. Relevant equations

the "and" rule

3. The attempt at a solution

(.4) + (.7) - (.1) = 1

2. Jul 6, 2011

### the_amateur

first of all i think you should get a good book on probability since most of the problems posted by you are quite basic and you seem to be guessing the answers..

in this question

given is

P(A) = 0.7
P(B) = 0.4
P(A$^{c}$$\cap$B$^{c}$)= 0.1

you have to find P(A$\cap$B)

use

P(A$^{c}$$\cap$B$^{c}$) + P(A$\cup$B) =1