MathGrit
ProblemsTechniquesPricing
Sign inGet started
Back to problems

AIME 2005 I #2 — Arithmetic Sequences S_k First Term 1 Diff k

1800SpecialistCombinatoricsAlgebraSequences & SeriesCounting Principles

AIME I · 2005 · Problem 2

For each positive integer $ k, $ let $ S_k $ denote the increasing arithmetic sequence of integers whose first term is 1 and whose common difference is $ k. $ For example, $ S_3 $ is the sequence $ 1,4,7,10,\ldots. $ For how many values of $ k $ does $ S_k $ contain the term 2005?
0 students attempted0% solvedRating 1800

Related practice paths

AIME PracticeInteger-answer practice for deeper multi-step problems.How to Qualify for AIMEScore goals, contest choice, and prep habits for AIME hopefuls.AIME Practice StrategyHow to improve accuracy on high-difficulty problems.

Ready to check your answer?

Create an account to submit answers, save history, and track your rating.

Progressive Hints5

Unlock hints one at a time — each reveals a little more without spoiling the solution.

Step-by-Step Solutions1

Multiple solution approaches with detailed walkthroughs, unlocked after you solve the problem.

AI-Powered Grading

Instant feedback on your answer — handles fractions, decimals, and equivalent forms.

Curated problem bank

Supported tracks for AMC, AIME, MATHCOUNTS, and olympiad-style training, plus global problem sources like UKMT, Euclid, and Kangaroo.