A box is filled with 9 brown cards, 2 blue cards, and 9 yellow cards. A card is chosen at random from the box. What is the probability that it is a brown or a yellow card?

18/20

Step-by-step explanation:

There are 20 cards in total. The 9 yellow and brown cards makes 18 cards. Since we want the yellow or brown, the probability is 18 out of 20 cards.