B) the first marble is replaced, and another marble is chosen at random. if you're told the marble has the number 6 on it, what is the probability the marble is blue?

A) 1/5 (since you know it is red you can focus on the reds 1-5. Then you just have a 1 in 5 chance of it being number 3) 

B) 1/2 (there is only 2 marbles with the number 1 on it. So its a 50/50 chance its red.) 

Also ivorbigg has no clue what he/she is talking about. A probably never has a value higher than 1. If it did, that would mean that is more than 100% chance of that event happening which is impossible. All of your answers to anything probability related is 1 or less.