Question

14. suppose that the probability that Susie will go downtown is 26%. Also suppose that if susie goes downtown, then the probability that she will stop by a coffee shop is 58%. Find the probability that Susie will go downtown and stop at a coffee shop.

possible answers :

A 0.1508, B 0.1708, C 0.1908, D 0.2108

Answer 1

Solution:

Given:

P( Susie will go downtown ) = 26% = 0.26

P( Susie will stop by a coffee shop given she will go downtown ) = 58% = 0.58

Let A = Susie will go downtown and B = Susie will stop by a coffee shop

So we have have:

P(A) = 0.26

and P( B | A) = 0.58

We have to find:

P( Susie will go downtown and stop at a coffee shop ) = ............?

That is we have to find:

P( A and B) = ........?

Using conditional rule of probability :

That is:

that is:

Thus the probability that Susie will go downtown and stop at a coffee shop = 0.1508