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

(Created page with "== Problem == Four ordinary, six-sided, fair dice are tossed. What is the probability that the sum of the numbers on top is <math>5</math>? == Solution == == See Also == {{U...")
 
(Solution)
 
(3 intermediate revisions by one other user not shown)
Line 6: Line 6:
  
 
== Solution ==
 
== Solution ==
 
+
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>
 +
~SharpApricot123
  
 
== See Also ==
 
== See Also ==
{{UNC Math Contest box|n=II|year=2012|num-b=1|num-a=3}}
+
{{UNCO Math Contest box|n=II|year=2012|num-b=1|num-a=3}}
  
 
[[Category:Introductory Probability Problems]]
 
[[Category:Introductory Probability Problems]]

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