how do i solve the P(red or blue) when there are 12 marbles, and 6 are red and 3 are blue?

Question

There are 12 marbles in a bag, 6 are red, 3 are blue, and 3 are yellow.  What is the probability of drawing a red marble or blue marble?  How do I set it up?

Answer 1

Well half 1/2 of them are red so you'd have 1/2 the chance of drawing a reed marble scince there are 6 maarbles and 12 marbles in total. Then you'd have a 1/4 chance of drawing a blue marble scine there 12 marbles and 3 blue, You can set it up by counting for example, for the blue, 3,6,9,12, you know you can divide it into 4ths, and so on from there! Good Luck!!!