Difference between revisions of "2012 UNCO Math Contest II Problems/Problem 2"

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== Solution ==
 
== Solution ==
 
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The total possibilities when we roll 4 fair 6-sided dice is <math>6\cdot 6\cdot 6\cdot 6=1296.</math> We see that the only possible way for these dice to have a sum of <math>5</math> is to have <math>3</math> dice with ones on it and one dice with a <math>2</math> on it. This can be done in <math>4</math> ways. Thus, the probability is <cmath>\frac{4}{1296}=\boxed{\frac{1}{324}}</cmath>
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~SharpApricot123
  
 
== See Also ==
 
== See Also ==

Latest revision as of 16:25, 18 November 2020

Problem

Four ordinary, six-sided, fair dice are tossed. What is the probability that the sum of the numbers on top is $5$?


Solution

The total possibilities when we roll 4 fair 6-sided dice is $6\cdot 6\cdot 6\cdot 6=1296.$ We see that the only possible way for these dice to have a sum of $5$ is to have $3$ dice with ones on it and one dice with a $2$ on it. This can be done in $4$ ways. Thus, the probability is \[\frac{4}{1296}=\boxed{\frac{1}{324}}\] ~SharpApricot123

See Also

2012 UNCO Math Contest II (ProblemsAnswer KeyResources)
Preceded by
Problem 1
Followed by
Problem 3
1 2 3 4 5 6 7 8 9 10
All UNCO Math Contest Problems and Solutions