 # 2021 AIME I Answer Key Released Posted by

Yesterday, selected middle school and high school students participated in this year’s AIME I Competition (including some students proctored by Areteem online).

The problems can now be discussed! See below for the answer key for the 2021 AIME I questions as well as the concepts tested on each problem. All answers for the AIME are in the form of 3-digit integers.

1
97
combinatorics: probability and independence
2
109
geometry: areas, rectangles, and similar triangles
3
50
number theory: counting, factoring, and cases
4
331
combinatorics: counting, cases, and overcounting
5
31
algebra: arithmetic sequences, factoring, and equations
6
192
geometry: 3D space, points, distances, and equations
7
63
algebra and number theory: trigonometric equations and mods
8
57
algebra: absolute values, symmetry, and cases
9
567
geometry: trapezoids, similar triangles, and Ptolemy’s theorem
10
59
number theory: recursive sequences, GCDs, and Euclidean Algorithm
11
301
12
19
combinatorics: expected values, states, and conditional expectation
13
672
geometry: circles, radical axis, and triangles
14
125
number theory: primes, divisors, and multiplicative orders
15
285
algebra: equations for conics and factoring

Want to practice more AMC and AIME Problems? Check out the Zoom International Math League (ZIML) practice page here for practice resources, including Mock Exams and old Exams.

The AIME I exam is administered by the Mathematical Association of America (MAA). Students are invited to take the AIME based on their scores for the AMC 10 and 12 exams. For general information about the AMC 10 and 12, click here.