Question 571828: Hello,
I'm having really hard time with probability questions on my homeworks that are being graded.
heres the question: A die is thrown until a 6 comes up, but only five times if no 6 comes up in 5 throws. How many possible sequences of numbers can come up?
I tried and thought the answer would be 6^5. This is because on die there is 6 numbers so every roll is 6 possible ways. And it can only go up to 5 throws so 6^5? I'm not sure because right now we are learning about permutations and combinations but i dont know how it relates.
I hope you guys can be able to answer this in one day hopefully, i procrastinated. next time ill email my questions faster.
Thanks so much!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A die is thrown until a 6 comes up, but only five times if no 6 comes up in 5 throws. How many possible sequences of numbers can come up?
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If 6 comes up on 1st throw: the only sequence is "6"
If 6 comes up on 2nd throw: 16,26,36,46,56
If 6 comes on 3rd throw: there are 5*5 = 25 patterns preceeding the 6
If 6 comes on the 4th throw: there are 5^3 = 125 patterns before the 6
if 6 comes on the 5th throw: there are 5^4 = 625 patterns before the 6
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Count to get the total number of sequences.
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Cheers,
San H.
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