IKMC 2027 - Grades 7-8 - Self-study SET 9 - Thematic Batch 3 Question 16

Ank has fifteen straight sticks of lengths 1 cm, 2 cm, 3 cm,...,15 cm. What is the greatest number of congruent equilateral triangles he can make using every stick without breaking any?

Interpretation: separate triangles, no shared sticks; sides may be assembled end to end.