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C. 1109. There were 14 multiple choice questions on a quiz, with 4 answers to each question. The best score was 10. What is the probability of achieving this score if the answers are selected at random?

(5 points)

Deadline expired on 10 February 2012.

Google Translation (Sorry, the solution is published in Hungarian only.)

Megoldás.

$\displaystyle \binom{14}{10}\cdot \left ( \frac 14\right)^{10} \cdot \left ( \frac 34\right)^{4}\approx 0,0003.$

Statistics on problem C. 1109.
 280 students sent a solution. 5 points: 184 students. 4 points: 8 students. 3 points: 11 students. 2 points: 40 students. 1 point: 16 students. 0 point: 9 students. Unfair, not evaluated: 12 solutions.

• Problems in Mathematics of KöMaL, January 2012

•  Támogatóink: Morgan Stanley