Probability Help

[swgd23]

I am confused as to which rule applies to this question but if someone can help me id greatly appreciate it!!

Ok so heres the question:

There is a gumball machine containing 3 Green, 4 red, and 7 blue gumballs

What is the probability of randomly picking a red gumball and then a blue gumball assuming:

a) You replace the red gumball before you pick the blue gumball

b) You DO NOT replace the red gumball before you pick the blue gumball


Heres my answers so far but I just want to double check my reasoning:

A) 7/14 - 4/13 = 7/14 = .21 or 21%

B) (4/14)(7/13) = 28/182 = .153 or 15%



Please if anyone can help/review my questions and answers id greatly appreciate it!! thanks!

 

[Denis]

IThere is a gumball machine containing 3 Green, 4 red, and 7 blue gumballs
What is the probability of randomly picking a red gumball and then a blue gumball assuming:
a) You replace the red gumball before you pick the blue gumball
b) You DO NOT replace the red gumball before you pick the blue gumball

Were you absent during probability classes?

a) 4/14 times 7/14
b) 4/14 times 7/13