## Precalculus (6th Edition) Blitzer

The probability that a red 7 or a black 8 card is dealt from a pack of 52 cards is $\frac{1}{13}$.
We know that the total number of "7 red" cards in a deck is 2 and the total number of "8 black" cards in a deck is 2. Therefore, the total number of favorable outcomes is $=2+2=4$ And the probability that a 7 of red or an 8 of black card is dealt is given below, \begin{align} & P\left( \text{dealt a 7 of red or a 8 of black} \right)=\frac{\text{number of red 7 and black 8 cards}}{\text{total number of cards in the deck}} \\ & =\frac{4}{52} \\ & =\frac{1}{13} \end{align} Thus, the probability that a red 7 or a black 8 card is dealt is $\frac{1}{13}$.