Library / /108 of 413

, 2008

Number theory Difficulty 1.0 Junior Find the answer Canada

The numbers $3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13$ are written on separate cards and placed face down on a table. A card is chosen at random and flipped over. What is the probability that the number on this card is a prime number?

(A) $\frac{2}{11}$ (B) $\frac{4}{11}$ (C) $\frac{6}{11}$ (D) $\frac{3}{11}$ (E) $\frac{5}{11}$

Want a route through all this instead of an archive? The track puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.