The AMC 10B and 12B Competitions were held yesterday. Congrats to the thousands who competed!
The problems can now be discussed. See below for answer keys and concepts tested for every problem on the 2025 AMC 10B and AMC 12B held on November 13th, 2025.
2025 AMC 10B Answers
1
B
arithmetic: quotients
2
D
number theory: remainders, patterns, and sums
3
D
algebra and combinatorics: Pascal’s triangle and patterns
4
A
number theory: bases and equations
5
C
geometry: triangles, circumcircles, and inscribed angles
6
C
geometry: areas, similar triangles, and area ratios
7
C
geometry: distances, Pythagorean theorem, and equations
8
C
number theory: place values, digits, and modular arithmetic
9
C
algebra and combinatorics: systems of inequalities and counting
10
A
algebra: rational functions and polynomial long division
11
B
combinatorics: counting derangements and probability
12
C
geometry: areas, inscribed circles, and symmetry
13
A
geometry: altitudes, medians, and similar triangles
14
C
combinatorics: choosing groups and probability
15
D
algebra: factoring, partial sums, and telescoping series
16
D
combinatorics: counting, colors, and cases
17
B
algebra: averages, recursive sequences, and patterns
18
D
algebra and number theory: square roots, floors, and sums of squares
19
D
geometry: similar solids, volumes, and ratios
20
A
geometry: circles, tangents, and special triangles
21
C
combinatorics: symmetry, parity, and paths
22
A
combinatorics and number theory: divisibility rules, stars and bars, and counting
23
C
algebra and number theory: linear Diophantine equations
24
E
combinatorics: probability states and systems of equations
25
B
geometry and number theory: paths, reflections, symmetry, and Diophantine equations
2025 AMC 12B Answers
1
B
arithmetic: quotients
2
D
number theory: remainders, patterns, and sums
3
D
algebra: complex numbers
4
A
number theory and algebra: number bases and equations
5
E
number theory: linear Diophantine equations
6
C
number theory: place values, digits, and modular arithmetic
7
C
algebra: logarithms, logarithm rules, and telescoping sums
8
C
algebra: roots, conjugates, and Vieta’s theorem
9
C
number theory: modular arithmetic and patterns
10
A
geometry: altitudes, medians, and similar triangles
11
C
combinatorics: choosing groups and probability
12
C
geometry: special triangles, areas, and Cavalieri’s principle
13
D
combinatorics: counting, colors, and cases
14
B
algebra: averages, recursive sequences, and patterns
15
D
geometry: similar solids, volumes, and ratios
16
B
geometry: angles, trigonometry, and half-angle formulas
17
C
combinatorics: symmetry, parity, and paths
18
D
combinatorics: expected value, conditional probability, and geometric distributions
19
C
algebra and number theory: linear Diophantine equations
20
E
combinatorics: probability states and systems of equations
21
C
geometry: triangles, areas, and Pythagorean theorem
22
C
algebra and geometry: complex numbers, polar form, transformations, and areas
23
E
number theory: prime factorizations, modular arithmetic, and remainders
24
D
algebra: graphing, logarithms, sine graph, and periodicity
25
E
geometry: circumcircles, Ptolemy’s theorem, and law of cosines
In total, 12 questions of the same questions appeared on both the AMC 10B and AMC 12B. They are listed below:
AMC 10B
AMC 12B
1
1
2
2
4
4
8
6
13
10
14
11
16
13
17
14
19
15
21
17
23
19
24
20
Want to see the problems? The 2025 AMC 10B and 12B problems will be 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.
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