[Math] Three fair six-sided dice are tossed and the numbers showing on top are recorded.

combinatoricspermutations

I don't know if they are correct, these are my attempts

Three fair six-sided dice are tossed and the numbers
showing on top are recorded.

  1. How many different record sequences are possible?
  2. How many of the
    records contain exactly one six?
  3. How many of the
    records contain exactly 2 four?

1) Since order does matter, Say for example , (1,2,1) is a different sequence then (2,1,1) Therefore this is P(6,1)*P(6,1)*P(6.1)

2) Now, order does not seem to matter. So, C(6,1)*C(6,1)*C(1,1) Something tells me this is terribly wrong

3) C(6,1)*(C,1,1)*C(1,1)

Edit:

2) C(3,1)*P(5,1)*P(5,1)

3) C(3,2)*P(5,1)

Best Answer

Hint: You are right for 1. For 2, you have three ways to pick which slot gets the six and five ways to pick the number in each of the other two slots. For 3, you have (how many?) ways to pick the slots for the two fours and (how many?) ways to pick the value of the other die.

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