There are 5 red marbles, 2 Green marbles and 3 black marbles. What is the probability that red or black is chosen? (answer in decimal form)

Red - 50% chance (.5)

Black - 30% Chance (.3)

Explanation:

The total amount of marbles is ten, meaning that we can change it to 100% no problem.

Green - 2 = 20% =.2

Black - 3 = 30% =.3

Red - 5 = 50% =.5