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Paper Set
2015

2015 AMC10 Paper & Solutions Pick Paper A

25 questions with solutions, geometry focuses on triangle and quadrilateral areas, algebra on systems of equations.

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25 Questions
40 Minutes
Max Score 25
No Calculator
Exam Overview

Exam Overview

This exam emphasizes algebra, geometry, equations. Overall difficulty is moderate.

DDifficulty

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

TTopics

  • Algebra35%
  • Geometry30%
  • Number Theory15%
  • Combinatorics20%

AAwards

AIME Qualification
AIME Qualification (Top 2.5%)
105+
Honor Roll
Honor Roll (Top 5%)
100+
Achievement Roll
Grade 6 and below · 15+ points
88+
Sample Problems

2015 AMC10 Sample Problems (12 questions)

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

Q1EasyPolynomial
If f(x) = 2x² - 3x + 1, find f(5).
A) 36
B) 26
C) 31
D) 41
E) 46

Steps

1f(5) = 2×5² - 3×5 + 1
2= 2×25 - 15 + 1 = 36
Answer: ASubstitute, then exponentiate, multiply/divide, add/subtract
Q3EasyArithmetic Seq
Arithmetic sequence: a₁=6, d=2, find the 13-th term.
A) 22
B) 30
C) 26
D) 34
E) 38

Steps

1aₙ = a₁ + (n-1)d
2a_13 = 6 + 12×2 = 30
Answer: BGeneral term: aₙ=a₁+(n-1)d
Q5EasyExponent
If 2ˣ = 64, find x.
A) 4
B) 5
C) 6
D) 7
E) 8

Steps

164 = 2^6
2so x = 6
Answer: CConvert to same base, compare exponents
Q7EasyVieta's
Sum of roots of x² - 5x + 7 = 0?
A) 1
B) 3
C) 7
D) 5
E) 9

Steps

1Vieta's:sum of roots = -(-5)/1 = 5
2product of roots = 7
Answer: DFor x²-px+q=0, sum of roots = p
Q10MediumDivisibility
How many integers from 1 to 45 are divisible by 3?
A) 11
B) 13
C) 17
D) 19
E) 15

Steps

1⌊45 / 3⌋ = 15
Answer: ECount divisible by k: ⌊n/k⌋
Q12MediumDiagonals
How many diagonals does a regular 10-gon have?
A) 35
B) 29
C) 32
D) 38
E) 41

Steps

1diagonals = n(n-3)/2
2= 10×7/2 = 35
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 6^4 divided by 8.
A) 1
B) 2
C) 3
D) 0
E) 4

Steps

1compute 6^4 mod 8
2simplify step by step (modular arithmetic)
3=0
Answer: DModular arithmetic simplifies large exponents
Q22HardCompleting Sq
Find the minimum of f(x) = x² - 10x + 28.
A) 1
B) 5
C) 7
D) 9
E) 3

Steps

1complete the square:f(x) = (x - 5)² + 3
2when x = 5 , min at 3
Answer: ECompleting the square for quadratic extrema
Q24HardInclusion-Excl
4 distinct balls into 3 distinct boxes, each ≥1 ball, how many ways?
A) 36
B) 26
C) 31
D) 41
E) 46

Steps

1total 3^4 = 81
2subtract empty boxes: -C(3,1)×2^4 = -48
3add back 2 empty boxes: +C(3,2)×1 = +3
4total 81 - 48 + 3 = 36
Answer: AInclusion-exclusion handles 'at least'
Q25HardLaw of Cosines
In △ABC, a=5, b=6, cos C=1/2, find c².
A) 23
B) 31
C) 27
D) 35
E) 39

Steps

1Law of cosines c² = a² + b² - 2ab·cos C
2= 25 + 36 - 30 = 31
Answer: BLaw of cosines is key for solving triangles
Q1EasyPolynomial
If f(x) = 2x² - 5x + 1, find f(5).
A) 26
B) 18
C) 22
D) 30
E) 34

Steps

1f(5) = 2×5² - 5×5 + 1
2= 2×25 - 25 + 1 = 26
Answer: ASubstitute, then exponentiate, multiply/divide, add/subtract
Q3EasyArithmetic Seq
Arithmetic sequence: a₁=8, d=2, find the 13-th term.
A) 24
B) 32
C) 28
D) 36
E) 40

Steps

1aₙ = a₁ + (n-1)d
2a_13 = 8 + 12×2 = 32
Answer: BGeneral term: aₙ=a₁+(n-1)d
Q5EasyExponent
If 2ˣ = 64, find x.
A) 4
B) 5
C) 6
D) 7
E) 8

Steps

164 = 2^6
2so x = 6
Answer: CConvert to same base, compare exponents
Q7EasyVieta's
Sum of roots of x² - 7x + 7 = 0?
A) 3
B) 5
C) 9
D) 7
E) 11

Steps

1Vieta's:sum of roots = -(-7)/1 = 7
2product of roots = 7
Answer: DFor x²-px+q=0, sum of roots = p
Q10MediumDivisibility
How many integers from 1 to 47 are divisible by 3?
A) 11
B) 13
C) 17
D) 19
E) 15

Steps

1⌊47 / 3⌋ = 15
Answer: ECount divisible by k: ⌊n/k⌋
Q12MediumDiagonals
How many diagonals does a regular 12-gon have?
A) 54
B) 48
C) 51
D) 57
E) 60

Steps

1diagonals = n(n-3)/2
2= 12×9/2 = 54
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 6^4 divided by 8.
A) 1
B) 2
C) 3
D) 0
E) 4

Steps

1compute 6^4 mod 8
2simplify step by step (modular arithmetic)
3=0
Answer: DModular arithmetic simplifies large exponents
Q22HardCompleting Sq
Find the minimum of f(x) = x² - 10x + 30.
A) 1
B) 3
C) 7
D) 9
E) 5

Steps

1complete the square:f(x) = (x - 5)² + 5
2when x = 5 , min at 5
Answer: ECompleting the square for quadratic extrema
Q24HardInclusion-Excl
4 distinct balls into 3 distinct boxes, each ≥1 ball, how many ways?
A) 36
B) 26
C) 31
D) 41
E) 46

Steps

1total 3^4 = 81
2subtract empty boxes: -C(3,1)×2^4 = -48
3add back 2 empty boxes: +C(3,2)×1 = +3
4total 81 - 48 + 3 = 36
Answer: AInclusion-exclusion handles 'at least'
Q25HardLaw of Cosines
In △ABC, a=7, b=6, cos C=1/2, find c².
A) 33
B) 43
C) 38
D) 48
E) 53

Steps

1Law of cosines c² = a² + b² - 2ab·cos C
2= 49 + 36 - 42 = 43
Answer: BLaw of cosines is key for solving triangles

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