What is the probability of rolling two fair dice and

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What is the probability of rolling two fair dice and having at least one die show an even number?

A. 35/36
B. 3/4
C. 1/2
D. 1/4
E. 1/36

The OA is the option B.

Why is 3/4? I don't understand how can I get this number? Experts, can you help me? Thanks in advanced.

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by GMATGuruNY » Wed Feb 21, 2018 4:34 am
Vincen wrote:What is the probability of rolling two fair dice and having at least one die show an even number?

A. 35/36
B. 3/4
C. 1/2
D. 1/4
E. 1/36
P(at least 1 even number) = 1 - P(2 odd numbers).

Of the 6 numbers on a die, 1/2 are odd, 1/2 are even.
Thus:
P(2 odd numbers) = 1/2 * 1/2 = 1/4.
P(at least 1 even number) = 1 - 1/4 = 3/4.

The correct answer is B.
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by Scott@TargetTestPrep » Sun Jun 23, 2019 10:20 am
Vincen wrote:What is the probability of rolling two fair dice and having at least one die show an even number?

A. 35/36
B. 3/4
C. 1/2
D. 1/4
E. 1/36
We can use the formula:

P(at least one even) = 1 - P(no evens)

P(no evens) = 3/6 x 3/6 = 1/4.

P(at least one even) = 1 - 1/4 = 3/4.

Answer: B

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