What is the probability of picking a red marble from a bag of marbles that have blue and green marbles, I really need to know ASAP for my Math Quiz tomorrow. Thanks!

Well, the total of marbles (t), the amount of red (r) marbles.

Take the total of red marbles and put it into a ratio: (r)/(t)

But gobromash thanks for answering but isnt probability always a fraction.

Thats what my Math teacher Ms.CinCleare says to all the 5th graders.

A ratio is a fraction :P Look it up if you dont know what it means btw

You have to take the number of red marbles and divide it with the number of all the marbles.

red / red+blue+green