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Paper Set
2020

2020 AMC12 Paper & Solutions Pick Paper A

25 complete solutions, number theory weight increased with prime factorization and divisibility. Geometry focuses on area.

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25 Questions
75 Minutes
Max Score 150
No Calculator
Exam Overview

Exam Overview

>, Area.

DDifficulty

  • EasyQ1-10
  • MediumQ11-20
  • HardQ21-25

TTopics

  • Algebra30%
  • Geometry30%
  • Number Theory25%
  • Combinatorics15%

AAwards

AIME Qualification
AIME Qualification (Top 2.5%)
93+
Honor Roll
Honor Roll (Top 5%)
79+
Achievement Roll
Grade 10 and below
62+
Sample Problems

2020 AMC12 Sample Problems (12 questions)

Sample reference problems by difficulty — click an option to check your answer

Q1EasyPolynomial
If f(x) = 2x² - 3x + 3, find f(2).
A) 5
B) 1
C) 3
D) 7
E) 9

Steps

1f(2) = 2×2² - 3×2 + 3
2= 2×4 - 6 + 3 = 5
Answer: ASubstitute, then exponentiate, multiply/divide, add/subtract
Q3EasyArithmetic Seq
Arithmetic sequence: a₁=3, d=2, find the 12-th term.
A) 19
B) 25
C) 22
D) 28
E) 31

Steps

1aₙ = a₁ + (n-1)d
2a_12 = 3 + 11×2 = 25
Answer: BGeneral term: aₙ=a₁+(n-1)d
Q5EasyExponent
If 4ˣ = 64, find x.
A) 1
B) 2
C) 3
D) 4
E) 5

Steps

164 = 4^3
2so x = 3
Answer: CConvert to same base, compare exponents
Q7EasyVieta's
Sum of roots of x² - 5x + 4 = 0?
A) 1
B) 3
C) 7
D) 5
E) 9

Steps

1Vieta's:sum of roots = -(-5)/1 = 5
2product of roots = 4
Answer: DFor x²-px+q=0, sum of roots = p
Q10MediumDivisibility
How many integers from 1 to 30 are divisible by 5?
A) 2
B) 4
C) 8
D) 10
E) 6

Steps

1⌊30 / 5⌋ = 6
Answer: ECount divisible by k: ⌊n/k⌋
Q12MediumDiagonals
How many diagonals does a regular 9-gon have?
A) 27
B) 21
C) 24
D) 30
E) 33

Steps

1diagonals = n(n-3)/2
2= 9×6/2 = 27
Answer: An-gon diagonals: n(n-3)/2
Q15MediumCombination
Compute C(6, 3).
A) 14
B) 20
C) 17
D) 23
E) 26

Steps

1C(n,3) = n(n-1)(n-2)/6
2= 6×5×4/6 = 20
Answer: BCombination: C(n,k)=n!/(k!(n-k)!)
Q17MediumPythagorean
Right triangle legs 3 and 4, find the hypotenuse.
A) 1
B) 3
C) 5
D) 7
E) 9

Steps

1c² = 3² + 4² = 9 + 16 = 25
2c = √25 = 5
Answer: CPythagorean theorem a²+b²=c²
Q20HardModular Arith
Find the remainder of 3^6 divided by 5.
A) 2
B) 3
C) 5
D) 4
E) 6

Steps

1compute 3^6 mod 5
2simplify step by step (modular arithmetic)
3=4
Answer: DModular arithmetic simplifies large exponents
Q22HardCompleting Sq
Find the minimum of f(x) = x² - 4x + 9.
A) 1
B) 3
C) 7
D) 9
E) 5

Steps

1complete the square:f(x) = (x - 2)² + 5
2when x = 2 , min at 5
Answer: ECompleting the square for quadratic extrema
Q24HardInclusion-Excl
6 distinct balls into 3 distinct boxes, each ≥1 ball, how many ways?
A) 540
B) 430
C) 485
D) 595
E) 650

Steps

1total 3^6 = 729
2subtract empty boxes: -C(3,1)×2^6 = -192
3add back 2 empty boxes: +C(3,2)×1 = +3
4total 729 - 192 + 3 = 540
Answer: AInclusion-exclusion handles 'at least'
Q25HardLaw of Cosines
In △ABC, a=7, b=8, cos C=1/2, find c².
A) 45
B) 57
C) 51
D) 63
E) 69

Steps

1Law of cosines c² = a² + b² - 2ab·cos C
2= 49 + 64 - 56 = 57
Answer: BLaw of cosines is key for solving triangles
Q1EasyPolynomial
If f(x) = 2x² - 5x + 3, find f(2).
A) 1
B) 3
C) 5
D) 7
E) 9

Steps

1f(2) = 2×2² - 5×2 + 3
2= 2×4 - 10 + 3 = 1
Answer: ASubstitute, then exponentiate, multiply/divide, add/subtract
Q3EasyArithmetic Seq
Arithmetic sequence: a₁=5, d=2, find the 12-th term.
A) 21
B) 27
C) 24
D) 30
E) 33

Steps

1aₙ = a₁ + (n-1)d
2a_12 = 5 + 11×2 = 27
Answer: BGeneral term: aₙ=a₁+(n-1)d
Q5EasyExponent
If 4ˣ = 64, find x.
A) 1
B) 2
C) 3
D) 4
E) 5

Steps

164 = 4^3
2so x = 3
Answer: CConvert to same base, compare exponents
Q7EasyVieta's
Sum of roots of x² - 7x + 4 = 0?
A) 3
B) 5
C) 9
D) 7
E) 11

Steps

1Vieta's:sum of roots = -(-7)/1 = 7
2product of roots = 4
Answer: DFor x²-px+q=0, sum of roots = p
Q10MediumDivisibility
How many integers from 1 to 32 are divisible by 5?
A) 2
B) 4
C) 8
D) 10
E) 6

Steps

1⌊32 / 5⌋ = 6
Answer: ECount divisible by k: ⌊n/k⌋
Q12MediumDiagonals
How many diagonals does a regular 11-gon have?
A) 44
B) 38
C) 41
D) 47
E) 50

Steps

1diagonals = n(n-3)/2
2= 11×8/2 = 44
Answer: An-gon diagonals: n(n-3)/2
Q15MediumCombination
Compute C(8, 3).
A) 44
B) 56
C) 50
D) 62
E) 68

Steps

1C(n,3) = n(n-1)(n-2)/6
2= 8×7×6/6 = 56
Answer: BCombination: C(n,k)=n!/(k!(n-k)!)
Q17MediumPythagorean
Right triangle legs 6 and 8, find the hypotenuse.
A) 6
B) 8
C) 10
D) 12
E) 14

Steps

1c² = 6² + 8² = 36 + 64 = 100
2c = √100 = 10
Answer: CPythagorean theorem a²+b²=c²
Q20HardModular Arith
Find the remainder of 3^6 divided by 5.
A) 2
B) 3
C) 5
D) 4
E) 6

Steps

1compute 3^6 mod 5
2simplify step by step (modular arithmetic)
3=4
Answer: DModular arithmetic simplifies large exponents
Q22HardCompleting Sq
Find the minimum of f(x) = x² - 4x + 11.
A) 3
B) 5
C) 9
D) 11
E) 7

Steps

1complete the square:f(x) = (x - 2)² + 7
2when x = 2 , min at 7
Answer: ECompleting the square for quadratic extrema
Q24HardInclusion-Excl
6 distinct balls into 3 distinct boxes, each ≥1 ball, how many ways?
A) 540
B) 430
C) 485
D) 595
E) 650

Steps

1total 3^6 = 729
2subtract empty boxes: -C(3,1)×2^6 = -192
3add back 2 empty boxes: +C(3,2)×1 = +3
4total 729 - 192 + 3 = 540
Answer: AInclusion-exclusion handles 'at least'
Q25HardLaw of Cosines
In △ABC, a=9, b=8, cos C=1/2, find c².
A) 57
B) 73
C) 65
D) 81
E) 89

Steps

1Law of cosines c² = a² + b² - 2ab·cos C
2= 81 + 64 - 72 = 73
Answer: BLaw of cosines is key for solving triangles

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