2023 AMC 10 B

Complete problem set with solutions and individual problem pages

Problem 1 Easy

Mrs. Jones is pouring orange juice into four identical glasses for her four sons. She fills the first three glasses completely but runs out of juice when the fourth glass is only \frac { 1 } { 3 } full. What fraction of a glass must Mrs. Jones pour from each of the first three glasses into the fourth glass so that all four glasses will have the same amount of juice? (2023 AMC10B Q1)

  • A.

    \frac { 1 } { 1 2 }

  • B.

    \frac { 1 } { 4 }

  • C.

    \frac { 1 } { 6}

  • D.

    \frac { 1 } { 8 }

  • E.

    \frac { 2 } { 9 }

Answer:C
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Problem 2 Easy

Carlos went to a sports store to buy running shoes. Running shoes were on sale, with prices reduced by 20%on every pair of shoes. Carlos also knew that he had to pay a 7.5% sales tax on the discounted price. He had 43 dollars. What is the original (before discount) price of the most expensive shoes he could afford to buy? (2023 AMC10B Q2)

  • A.

    $46

  • B.

    $50

  • C.

    $48

  • D.

    $47

  • E.

    $49

Answer:B
Link Problem
Problem 3 Easy

A 3 -4-5 right triangle is inscribed in circle A, and a 5 -12-13 right triangle is inscribed in circle B

What is the ratio of the area of circle A to the area of circle B? (2023 AMC10B Q3)

  • A.

    \frac { 9 } { 2 5 }

  • B.

    \frac { 1 } { 9 }

  • C.

    \frac { 1 } { 5 }

  • D.

    \frac { 2 5 } { 1 6 9 }

  • E.

    \frac { 4 } { 2 5 }

Answer:D
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Problem 4 Easy

Jackson's paintbrush makes a narrow strip with a width of 6.5 milimeters. Jackson has enough paint to make a strip 25 meters long. How many square centimeters of paper could Jackson cover with paint? (2023 AMC10B Q4)

  • A.

    162,500

  • B.

    162.5

  • C.

    1,625

  • D.

    1,625,000

  • E.

    16,250

Answer:C
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Problem 5 Easy

Maddy and Lara see a list of numbers written on a blackboard. Maddy adds 3 to each number in the list and finds that the sum of her new numbers is 45. Lara multiplies each number in the list by 3 and finds that the sum of her new numbers is also 45. How many numbers are written on the blackboard? (2023 AMC10B Q5)

  • A.

    10

  • B.

    5

  • C.

    6

  • D.

    8

  • E.

    9

Answer:A
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Problem 6 Easy

L _ { 1 } = 1 , L _ { 2 } = 3, and L _ { n + 2 } = L _ { n + 1 } + L _ { n } for n \geq 1 . How many terms in the sequence L _ { 1 }, L _ { 2 }, L _ { 3 }, \cdots , L _ { 2 0 2 3 } are even? (2023 AMC10B Q6)

  • A.

    673

  • B.

    1011

  • C.

    675

  • D.

    1010

  • E.

    674

Answer:E
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Problem 7 Easy

Square ABCD is rotated 20° clockwise about its center to obtain square EFGH, as shown below. What is the degree measure of \angle EAB ?(2023 AMC10B Q7)

  • A.

    2 4 ^ { \circ }

  • B.

    3 5 ^ { \circ }

  • C.

    3 0 ^ { \circ }

  • D.

    3 2 ^ { \circ }

  • E.

    2 0 ^ { \circ }

Answer:B
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Problem 8 Easy

What is the units digit of 2022 ^ { 2 0 2 3 }+2 0 2 3 ^ { 2 0 2 2 }? (2023 AMC10B Q8)

  • A.

    7

  • B.

    1

  • C.

    9

  • D.

    5

  • E.

    3

Answer:A
Link Problem
Problem 9 Easy

The numbers 16 and 25 are a pair of consecutive positive squares whose difference is 9. How many pairs of consecutive positive perfect squares have a difference of less than or equal to 2023? (2023 AMC10B Q9)

  • A.

    674

  • B.

    1011

  • C.

    1010

  • D.

    2019

  • E.

    2017

Answer:B
Link Problem
Problem 10 Medium

You are playing a game. A 2 \times 1 rectangle covers two adjacent squares (oriented either horizontally or vertically) of a 3 \times 3 grid of squares, but you are not told which two squares are covered. Your goal is to find at least one square that is covered by the rectangle. A "turn" consists of you guessing a square, after which you are told whether that square is covered by the hidden rectangle. What is the minimum number of turns you need to ensure that at least one of your guessed squares is covered by the rectangle? (2023 AMC10B Q10)

  • A.

    3

  • B.

    5

  • C.

    4

  • D.

    8

  • E.

    6

Answer:C
Link Problem
Problem 11 Easy

Suzanne went to the bank and withdrew $800. The teller gave her this amount using $20 bills, $50 bills, and $100 bills, with at least one of each denomination. How many different collections of bills could Suzanne have received? (2023 AMC10B Q11)

  • A.

    45

  • B.

    21

  • C.

    36

  • D.

    28

  • E.

    32

Answer:B
Link Problem
Problem 12 Medium

When the roots of the polynomial

P ( x ) = \prod _ { i = 1 } ^ { 1 0 } ( x - i ) ^ { i }

are removed from the real number line, what remains is the union of 11 disjoint open intervals. On how many of those intervals is P(x) positive? (2023 AMC10B Q12)

  • A.

    3

  • B.

    4

  • C.

    5

  • D.

    6

  • E.

    7

Answer:C
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Problem 13 Easy

What is the area of the region in the coordinate plane defined by the inequality

| | x | - 1 | + | | y | - 1 | \leq 1 ? (2023 AMC10B Q13)

  • A.

    4

  • B.

    8

  • C.

    10

  • D.

    12

  • E.

    15

Answer:B
Link Problem
Problem 14 Medium

How many ordered pairs of integers (m, n) satisfy the equation m ^ { 2 } + m n + n ^ { 2 } = m ^ { 2 } n ^ { 2 } ? (2023 AMC10B Q14)

  • A.

    7

  • B.

    1

  • C.

    3

  • D.

    6

  • E.

    5

Answer:C
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Problem 15 Easy

What is the least positive integer m such that m·2!·3!·4!·5!\cdots 16! is a perfect square? (2023 AMC10B Q15)

  • A.

    30

  • B.

    30030

  • C.

    70

  • D.

    1430

  • E.

    1001

Answer:C
Link Problem
Problem 16 Medium

Define an upno to be a positive integer of 2 or more digits where the digits are strictly increasing moving left to right. Similarly, define a downno to be a positive integer of 2 or more digits where the digits are strictly decreasing moving left to right. For instance, the number 258 is an upno and 8620 is a downno. Let U equal the total number of upnos and let D equal the total number of downnos. What is|U - D|? (2023 AMC10B Q16)

  • A.

    512

  • B.

    10

  • C.

    0

  • D.

    9

  • E.

    511

Answer:E
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Problem 17 Medium

A rectangular box P has distinct edge lengths a, b, and c. The sum of the lengths of all 12 edge of P is 13, the sum of the areas of all 6 faces of P is \frac { 1 1 } { 2 }, and the volume of P is \frac { 1 } { 2 }. What is the length of the longest interior diagonal connecting two vertices of P? (2023 AMC10B Q17)

  • A.

    2

  • B.

    \frac { 3 } { 8 }

  • C.

    \frac { 9 } { 8 }

  • D.

    \frac { 9 } { 4 }

  • E.

    \frac { 3 } { 2 }

Answer:D
Link Problem
Problem 18 Medium

Suppose a, b, and c are positive integers such that

\frac { a } { 1 4 } + \frac { b } { 1 5 } = \frac { c } { 2 1 0 } .

Which of the following statements are necessarily true?

I.If gcd(a,14) = 1 or gcd(b,15) = 1 or both, then gcd(c,210) = 1.

II.If gcd(c,210) =1, then gcd(a,14)=1 or gcd(b,15) = 1 or both.

III.gcd(c,210) =1 if and only if gcd(a,14) = gcd(b,15)=1. (2023 AMC10B Q18)

  • A.

    l,II, and ll

  • B.

    l only

  • C.

    l and ll only

  • D.

    Ⅲ only

  • E.

    II and Ⅲ only

Answer:E
Link Problem
Problem 19 Hard

Sonya the frog chooses a point uniformly at random lying within the square [0, 6] \times  [0,6] in the coordinate plane and hops to that point. She then randomly chooses a distance uniformly at random from (0, 1] and a direction uniformly at random from north, south east, west. All he choices are independent. She now hops the distance in the chosen direction. What is the probability that she lands outside the square? (2023 AMC10B Q19)

  • A.

    \frac { 1 } { 6 }

  • B.

    \frac { 1 } { 1 2 }

  • C.

    \frac { 1 } { 4 }

  • D.

    \frac { 1 } { 1 0 }

  • E.

    \frac { 1 } { 9 }

Answer:B
Link Problem
Problem 20 Medium

Four congruent semicircles are drawn on the surface of a sphere with radius 2, as shown, creating a close curve that divides the surface into two congruent regions. The length of the curcve is \pi \sqrt { n }. What is n? (2023 AMC10B Q20)

  • A.

    32

  • B.

    12

  • C.

    48

  • D.

    36

  • E.

    27

Answer:A
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Problem 21 Hard

Each of 2023 balls is placed in on of 3 bins. Which of the following is closest to the probability that each of the bins will contain an odd number of balls? (2023 AMC10B Q21)

  • A.

    \frac { 2 } { 3 }

  • B.

    \frac { 3 } { 1 0 }

  • C.

    \frac { 1 } { 2 }

  • D.

    \frac { 1 } { 3 }

  • E.

    \frac { 1 } { 4 }

Answer:E
Link Problem
Problem 22 Medium

How many distinct values of x satisfy [ x ] ^ { 2 } - 3 x + 2 = 0 where [x] denotes the largest integer less than or equal to x? (2023 AMC10B Q22)

  • A.

    an infinite number

  • B.

    4

  • C.

    2

  • D.

    3

  • E.

    0

Answer:B
Link Problem
Problem 23 Medium

An arithmetic sequence has n≥3 terms, initial term a and common difference d > 1. Carl wrote down all the terms in this sequence correctly except for one term which was off by 1. The sum of the terms was 222. What was a+d+n (2023 AMC10B Q23)

  • A.

    24

  • B.

    20

  • C.

    22

  • D.

    28

  • E.

    26

Answer:B
Link Problem
Problem 24 Medium

What is the perimeter of the boundary of the region consisting of all points which can be expressed as ( 2 u - 3 w , v + 4 w ) with 0 \leq u \leq 1 , 0 \leq v \leq 1 , and 0 \leq w \leq 1 ? (2023 AMC10B Q24)

  • A.

    10\sqrt { 3 }

  • B.

    10

  • C.

    12

  • D.

    18

  • E.

    16

Answer:E
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Problem 25 Hard

A regular pentagon with area \sqrt { 5 } + 1 is printed on paper and cut out. The five vertices of pentagon are folded into the center of the pentagon, creating a smaller pentagon. What is the area of the new pentagon? (2023 AMC10B Q25)

  • A.

    4 - \sqrt { 5 }

  • B.

    \sqrt { 5 } - 1

  • C.

    8 - 3 \sqrt { 5 }

  • D.

    \frac { \sqrt { 5 } + 1 } { 2 }

  • E.

    \frac { 2 + \sqrt { 5 } } { 3 }

Answer:B
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