In a standard set of dominoes, a face of each domino has a line through the center, with 0 to 6 dots on each side of the line. Each possible combination of dots is used exactly once, one combination per domino. What is the probability that a randomly selected domino will have the same number of dots on both sides of the line? Express your answer as a common fraction.

Question

I thought the answer was 1/7 did I make a mistake?

Answer 1

Yes, you made a mistake.

There are 7 dominoes out of 28 that have the same number on each side of the line.

Simplify 7/28

Answer 2

How do you know there are 28 dominoes?

Answer 3

It doesn't say in the question. So is it expecting us to know that a standard set has 28 dominoes?

Answer 4

I Googled.

http://www.google.com/#q=standard+set+of+dominoes

Answer 5

Yes. Today's students are expected to use Google to quickly and easily find facts.

Answer 6

Thanks

Answer 7

You're welcome.