# 2020 AMC 10B & AMC 12B Answer Key Released Posted by

Yesterday, thousands of middle school and high school students participated in this year’s AMC 10B and 12B Competition (including some students at Areteem Headquarters seen below).

The problems can now be discussed! See below for answer keys for both the 2020 AMC 10B and AMC 12B questions as well as the concepts tested on each problem.

1
D
arithmetic and negative numbers
2
E
geometry: cubes and volumes
3
E
algebra: ratios
4
D
geometry and number theory: primes numbers and angles in triangles
5
B
combinatorics: permutations with repeated objects
6
B
motion and palindromes
7
A
number theory: LCMs and perfect squares
8
D
geometry: right triangles and areas
9
D
number theory: diophantine equations
10
C
geometry: cones and volumes, lateral surfaces
11
D
combinatorics: probability
12
D
number theory: place values and arithmetic
13
B
geometry: coordinates and patterns
14
D
geometry: areas, hexagons, and circles
15
D
combinatorics: patterns and multiples
16
A
logic and game theory
17
C
combinatorics: cases and logic
18
B
combinatorics: probability and repetition
19
A
number theory: computation and modular arithmetic
20
B
geometry: volumes, prisms, cylinders, and spheres
21
B
geometry: areas, squares, right triangles
22
D
number theory: remainders, divisibility, and factoring
23
C
geometry: composing transformations
24
C
number theory: floor function and equations
25
A
combinatorics: permutations of products, cases, and patterns

1
C
arithmetic and square roots
2
A
algebra: arithmetic and factoring
3
E
algebra: ratios
4
D
geometry and number theory: primes numbers and angles in triangles
5
C
algebra: ratios and equations
6
D
number theory: factoring and simplifying
7
C
geometry: slopes, angles, and trigonometry
8
D
number theory: diophantine equations
9
C
geometry: cones and volumes, lateral surfaces
10
B
geometry: squares, inscribed circles, and power of a point
11
D
geometry: areas, hexagons, and circles
12
E
geometry: circles, chords, and power of a point
13
D
algebra: logarithms and square roots
14
A
logic and game theory
15
C
combinatorics: cases and logic
16
B
combinatorics: probability and repetition
17
C
algebra: polynomials, roots, and complex numbers
18
B
geometry: areas, squares, right triangles
19
C
geometry: composing transformations
20
D
combinatorics: probability, coloring cubes
21
C
number theory: floor function and equations
22
C
algebra: maximums, AM-GM inequality
23
B
algebra: complex numbers and polar coordinates
24
A
combinatorics: permutations of products, cases, and patterns
25
B
combinatorics: geometric probability, trigonometric functions, and maximums

In total 12 questions appeared on both the AMC 10B and AMC 12B. They are listed below:

 AMC 10B AMC 12B 3 3 4 4 9 8 10 9 14 11 16 14 17 15 18 16 21 18 23 19 24 21 25 24

Starting to prep for the AIME? Join one of Areteem’s AIME Prep courses to prepare for next month’s AIME. Click here for more details and registration. For answers to this year’s AMC 10A and 12A exams, click here. The 2020 AMC 10B and 12B problems are available on the ZIML site along with previous exams. Click here for AMC 10 and here for AMC 12.

The AMC 10 and 12 exams are administered by the Mathematical Association of America (MAA). For general information about the AMC 10 and 12, click here.