# Math Help - tree diagram

1. ## tree diagram

a library has five copies of a certain textbook on reserve of which two copies (1 and 2) are first printings and the other three (3,4,5) are second printings. a student examines these books in random order, stopping only when a second printing has been selected. how do you make a tree diagram for this problem?

2. ## Re: tree diagram

Originally Posted by amandacreed
a library has five copies of a certain textbook on reserve of which two copies (1 and 2) are first printings and the other three (3,4,5) are second printings. a student examines these books in random order, stopping only when a second printing has been selected. how do you make a tree diagram for this problem?

I will give the only three possible outcomes. Assuming that the student does not examine the same book twice

$\mathcal{P}(S)=\frac{3}{5}$

$\mathcal{P}(FS)=\frac{3}{10}$

$\mathcal{P}(FFS)=\frac{1}{10}$