Question 3
Rancho marks five points on paper and joins every pair by a straight segment. What is the largest number of triangles that the resulting drawing can contain?
Editorial consistency task: explain when the source answer 10 is correct, then prove the unrestricted visible-triangle maximum and identify whether any printed choice matches.
Original choices: A. 10; B. 20; C. 21; D. 12; E. 18
Editorial consistency task: explain when the source answer 10 is correct, then prove the unrestricted visible-triangle maximum and identify whether any printed choice matches.
Original choices: A. 10; B. 20; C. 21; D. 12; E. 18