2018 UNM-PNM Statewide High School Mathematics Contest II Problems/Problem 3

Revision as of 03:54, 10 August 2023 by Impromptua (talk | contribs) (Solution)

Problem

Let $a_1 < a_2 < a_3$ be three positive integers in the interval $[1,14]$ satisfying $a_2-a_1\ge3$ and $a_3-a_2\ge3$. How many different choices of $(a_1,a_2,a_3)$ exist?

Solution

just 10 choose 3 which is 120 i think

(no one will see this)

See also

2018 UNM-PNM Contest II (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
1 2 3 4 5 6 7 8 9 10
All UNM-PNM Problems and Solutions