Question 1200980
.
<pre>

(A)  The sample space consists of 4 possible events

         (guessed 1st answer;         guessed 2nd answer)

         (guessed 1st answer;     not guessed 2nd answer)

         (not guessed 1st answer;     guessed 2nd answer)

         (not guessed 1st answer; not guessed 2nd answer)



(B)  This probability is  {{{(4/5)*(4/5)}}} = {{{16/25}}}.



(C)  This probability is  {{{(1/5)*(1/5)}}} = {{{1/25}}}.



(D)  "At least one answer correct" is the complement to "no one answer is correct".

      The probability "no one answer is correct" is what we computed in (B): this probability is  {{{16/25}}}.


      Hence, the answer to (D) is 1 - {{{16/25}}} = {{{9/25}}}.
</pre>

Solved in full, with all questions answered.