A deck of card contains 2 of each - Red, Green, Blue and Yellow cards.
If 2 cards are drawn randomly from the deck, what is the probability that they both are not blue?
I can think of 2 approaches to solve this problem, both of which give me a different result!
Approach (1):- 1 - P(both are blue)
P(both are blue) = 1st card is blue AND 2nd card is blue
= (2/8) * (1/7) = 1/28
1 - (1/28) = 27/28 <--- Incorrect answer
Approach (2):- P(both are either red or yellow or green)
P(R,G,Y) = (6/8) * (5/7)
= 15/28 <---- Correct answer
Can someone please point out what is it that I'm not doing correctly in Approach (1)?
Also, I believe both approaches should render the same answer... if not, which one to choose while answering a question?
If 2 cards are drawn randomly from the deck, what is the probability that they both are not blue?
I can think of 2 approaches to solve this problem, both of which give me a different result!
Approach (1):- 1 - P(both are blue)
P(both are blue) = 1st card is blue AND 2nd card is blue
= (2/8) * (1/7) = 1/28
1 - (1/28) = 27/28 <--- Incorrect answer
Approach (2):- P(both are either red or yellow or green)
P(R,G,Y) = (6/8) * (5/7)
= 15/28 <---- Correct answer
Can someone please point out what is it that I'm not doing correctly in Approach (1)?
Also, I believe both approaches should render the same answer... if not, which one to choose while answering a question?
