# Use the special addition rule to determine the probability of drawing either a spade OR a heart from a standard deck of cards, on one draw from the deck.

Jan 29, 2015

The possibilies are exclusive (it's EITHER a spade OR a heart) and then you may add the probabilities.

13 spades + 13 hearts =26 "successes"

On a total of 52 this makes the probability:

26/52=1/2=50%

Remember :
either...or $\to$ add
and...and $\to$ multiply