Carcass wrote:
In a game, one player throws two fair, six-sided die at the same time. If the player receives at least a five or a one on either die, that player wins. What is the probability that a player wins after playing the game once?
A. 1/3
B. 4/9
C. 5/9
D. 2/3
E. 3/4
So, the player wins if he/she rolls
AT LEAST one 5 or 1.
When it comes to probability questions involving
"at least," it's best to try using the
complement.
That is, P(Event A happening) = 1 - P(Event A
not happening)
So, here we get: P(AT LEAST one 5 or 1) = 1 - P(zero 5's or 1's)
= 1 - P(no 5 or 1 on 1st die
AND no 5 or 1 on 2nd die)
= 1 - [P(no 5 or 1 on 1st die)
x P(no 5 or 1 on 2nd die)]
= 1 - [ 4/6
x 4/6]
= 1 - [16/36]
= 20/36
= 5/9
Answer: C
Cheers,
Brent