Difference between revisions of "1992 AHSME Problems/Problem 29"

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== Solution ==
 
== Solution ==
<math>\fbox{B}</math>
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<math>\fbox{D}</math>
  
 
== See also ==
 
== See also ==

Revision as of 16:24, 27 September 2014

Problem

An "unfair" coin has a $2/3$ probability of turning up heads. If this coin is tossed $50$ times, what is the probability that the total number of heads is even?

$\text{(A) } 25(\frac{2}{3})^{50}\quad \text{(B) } \frac{1}{2}(1-\frac{1}{3^{50}})\quad \text{(C) } \frac{1}{2}\quad \text{(D) } \frac{1}{2}(1+\frac{1}{3^{50}})\quad \text{(E) } \frac{2}{3}$

Solution

$\fbox{D}$

See also

1992 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 28
Followed by
Problem 30
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