Question 1042801
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A true/false test has 4 questions. What is the probability of getting at least 3 right by guessing the answers randomly?
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The full space of outcomes has  {{{2^4}}} = 16 elements.


The successive outcomes are  (a) 4 matching of 4 (only one),  and  (b) 3 matching of 4 (4 possibilities).


Hence,  the answer is  {{{(1+4)/16}}} = {{{5/16}}} = 0.3125.