probability with cards

[Bryn]

A man draws one card at random from a complete pack of 52 cards, replaces it and then draws another card at random from the pack.

 

Calculate the probibility that eaxactly one of the cards is a Queen.

 

I evaluated P(Q n Q') = 1/13 * 12/13 (they are independant events)

=12/169

 

The answer according to the book is 24/169 . Help!

[Bryn]

nevermind, got it now.

[Dave]

Just for the sake of showing the proof, either you get a queen first, or you get some other card then a queen. You just have to put the values in for the different probabilities.