Question 943753
Probability P (A or B), P (A and B) 
there are M&M candies in a jar: Red (7), Blue (7) and Yellow (7). 
==================
a) probability that randomly taken one candy is blue or red: 
P (Blue or Red) = P(blue) + P(red) = 7/21 + 7/21 = 14/21 = 2/3
---------------------------------------- 

b) probability that out of 2 candies randomly taken from the jar first candy will be Red and second candy will be Red again: 
P(Red and then Red) = P(red)*P(red|red) = (7/21)(6/20) = (1/3)(3/10) = 1/10
------------------
 Counting Outcomes (Permutations and Combinations) For numbers 8 and 2, in how many ways can you select 2 items out of 8 if order of selection makes a difference - use Permutations
8P2 = 8*7 = 56
------------------
 b) in how many ways can you select 2 items out of 8 if order of selection doesn't matter - use Combinations.
8C2 = (8*7)/(1*2) = 28
---------------------------
Cheers,
Stan H.
-------------