Difference between revisions of "2025 AIME II Problems"
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== Problem 1 == | == Problem 1 == | ||
− | Six points <math>A, B, C, D, E,</math> and <math>F</math> lie in a straight line in that order. Suppose that <math>G</math> is a point not on the line and that <math>AC=26, BD=22, CE=31, DF=33, AF=73, CG=40 | + | Six points <math>A, B, C, D, E,</math> and <math>F</math> lie in a straight line in that order. Suppose that <math>G</math> is a point not on the line and that <math>AC=26</math>, <math>BD=22</math>, <math>CE=31</math>, <math>DF=33</math>, <math>AF=73</math>, <math>CG=40</math>, and <math>DG=30.</math> Find the area of <math>\triangle BGE.</math> |
[[2025 AIME II Problems/Problem 1|Solution]] | [[2025 AIME II Problems/Problem 1|Solution]] | ||
== Problem 2 == | == Problem 2 == | ||
− | Find the sum of all positive integers <math>n</math> such that <math>n + 2</math> divides the product <math>3(n + 3)(n^2 + 9)</math> | + | |
+ | Find the sum of all positive integers <math>n</math> such that <math>n+2</math> divides the product <math>3(n+3)(n^2+9).</math> | ||
[[2025 AIME II Problems/Problem 2|Solution]] | [[2025 AIME II Problems/Problem 2|Solution]] | ||
==Problem 3== | ==Problem 3== | ||
− | Four unit squares form a <math>2 \times 2</math> grid. Each of the <math>12</math> unit line segments forming the sides of the squares is colored either red or blue in such a | + | Four unit squares form a <math>2 \times 2</math> grid. Each of the <math>12</math> unit line segments forming the sides of the squares is colored either red or blue in such a way that each unit square has <math>2</math> red sides and <math>2</math> blue sides. One example is shown below (red is solid, blue is dashed). Find the number of such colorings. |
+ | <asy> | ||
+ | size(4cm); | ||
+ | defaultpen(linewidth(1.2)); | ||
+ | draw((0, 0) -- (2, 0) -- (2, 1), red); | ||
+ | draw((0, 1) -- (1, 1) -- (1, 2) -- (2,2), red); | ||
+ | draw((0, 0) -- (0, 1),blue+dotted); | ||
+ | draw((1, 0) -- (1, 1) -- (2, 1) -- (2, 2),blue+dotted); | ||
+ | draw((0, 1) -- (0, 2) -- (1, 2),blue+dotted); | ||
+ | </asy> | ||
[[2025 AIME II Problems/Problem 3|Solution]] | [[2025 AIME II Problems/Problem 3|Solution]] | ||
==Problem 4== | ==Problem 4== | ||
− | + | The product<cmath>\prod^{63}_{k=4} \frac{\log_k (5^{k^2 - 1})}{\log_{k + 1} (5^{k^2 - 4})} = \frac{\log_4 (5^{15})}{\log_5 (5^{12})} \cdot \frac{\log_5 (5^{24})}{\log_6 (5^{21})}\cdot \frac{\log_6 (5^{35})}{\log_7 (5^{32})} \cdots \frac{\log_{63} (5^{3968})}{\log_{64} (5^{3965})}</cmath>is equal to <math>\tfrac mn,</math> where <math>m</math> and <math>n</math> are relatively prime positive integers. Find <math>m + n.</math> | |
[[2025 AIME II Problems/Problem 4|Solution]] | [[2025 AIME II Problems/Problem 4|Solution]] | ||
==Problem 5== | ==Problem 5== | ||
+ | Suppose <math>\triangle ABC</math> has angles <math>\angle BAC = 84^\circ, \angle ABC=60^\circ,</math> and <math>\angle ACB = 36^\circ.</math> Let <math>D, E,</math> and <math>F</math> be the midpoints of sides <math>\overline{BC}, \overline{AC},</math> and <math>\overline{AB},</math> respectively. The circumcircle of <math>\triangle DEF</math> intersects <math>\overline{BD}, \overline{AE},</math> and <math>\overline{AF}</math> at points <math>G, H,</math> and <math>J,</math> respectively. The points <math>G, D, E, H, J,</math> and <math>F</math> divide the circumcircle of <math>\triangle DEF</math> into six minor arcs, as shown. Find <math>\overarc{DE}+2\cdot \overarc{HJ} + 3\cdot \overarc{FG},</math> where the arcs are measured in degrees. | ||
+ | <asy> | ||
+ | import olympiad; | ||
+ | size(6cm); | ||
+ | defaultpen(fontsize(10pt)); | ||
+ | pair B = (0, 0), A = (Cos(60), Sin(60)), C = (Cos(60)+Sin(60)/Tan(36), 0), D = midpoint(B--C), E = midpoint(A--C), F = midpoint(A--B); | ||
+ | guide circ = circumcircle(D, E, F); | ||
+ | pair G = intersectionpoint(B--D, circ), J = intersectionpoints(A--F, circ)[0], H = intersectionpoints(A--E, circ)[0]; | ||
+ | draw(B--A--C--cycle); | ||
+ | draw(D--E--F--cycle); | ||
+ | draw(circ); dot(A);dot(B);dot(C);dot(D);dot(E);dot(F);dot(G);dot(H);dot(J); | ||
+ | label("$A$", A, (0, .8)); | ||
+ | label("$B$", B, (-.8, -.8)); | ||
+ | label("$C$", C, (.8, -.8)); | ||
+ | label("$D$", D, (0, -.8)); | ||
+ | label("$E$", E, (.8, .2)); | ||
+ | label("$F$", F, (-.8, .2)); | ||
+ | label("$G$", G, (0, .8)); | ||
+ | label("$H$", H, (-.2, -1)); | ||
+ | label("$J$", J, (.2, -.8)); | ||
+ | </asy> | ||
[[2025 AIME II Problems/Problem 5|Solution]] | [[2025 AIME II Problems/Problem 5|Solution]] | ||
==Problem 6== | ==Problem 6== | ||
+ | Circle <math>\omega_1</math> with radius <math>6</math> centered at point <math>A</math> is internally tangent at point <math>B</math> to circle <math>\omega_2</math> with radius <math>15</math>. Points <math>C</math> and <math>D</math> lie on <math>\omega_2</math> such that <math>\overline{BC}</math> is a diameter of <math>\omega_2</math> and <math>{\overline{BC} \perp \overline{AD}}</math>. The rectangle <math>EFGH</math> is inscribed in <math>\omega_1</math> such that <math>\overline{EF} \perp \overline{BC}</math>, <math>C</math> is closer to <math>\overline{GH}</math> than to <math>\overline{EF}</math>, and <math>D</math> is closer to <math>\overline{FG}</math> than to <math>\overline{EH}</math>, as shown. Triangles <math>\triangle {DGF}</math> and <math>\triangle {CHG}</math> have equal areas. The area of rectangle <math>EFGH</math> is <math>\frac{m}{n}</math>, where <math>m</math> and <math>n</math> are relatively prime positive integers. Find <math>m+n</math>. | ||
− | + | <asy> | |
+ | size(5cm); | ||
+ | defaultpen(fontsize(10pt)); | ||
+ | pair A = (9, 0), B = (15, 0), C = (-15, 0), D = (9, 12), E = (9+12/sqrt(5), -6/sqrt(5)), F = (9+12/sqrt(5), 6/sqrt(5)), G = (9-12/sqrt(5), 6/sqrt(5)), H = (9-12/sqrt(5), -6/sqrt(5)); | ||
+ | filldraw(G--H--C--cycle, lightgray); | ||
+ | filldraw(D--G--F--cycle, lightgray); | ||
+ | draw(B--C); | ||
+ | draw(A--D); | ||
+ | draw(E--F--G--H--cycle); | ||
+ | draw(circle((0,0), 15)); | ||
+ | draw(circle(A, 6)); | ||
+ | dot(A); | ||
+ | dot(B); | ||
+ | dot(C); | ||
+ | dot(D); | ||
+ | dot(E); | ||
+ | dot(F); | ||
+ | dot(G); | ||
+ | dot(H); | ||
+ | label("$A$", A, (.8, -.8)); | ||
+ | label("$B$", B, (.8, 0)); | ||
+ | label("$C$", C, (-.8, 0)); | ||
+ | label("$D$", D, (.4, .8)); | ||
+ | label("$E$", E, (.8, -.8)); | ||
+ | label("$F$", F, (.8, .8)); | ||
+ | label("$G$", G, (-.8, .8)); | ||
+ | label("$H$", H, (-.8, -.8)); | ||
+ | label("$\omega_1$", (9, -5)); | ||
+ | label("$\omega_2$", (-1, -13.5)); | ||
+ | </asy> | ||
[[2025 AIME II Problems/Problem 6|Solution]] | [[2025 AIME II Problems/Problem 6|Solution]] | ||
==Problem 7== | ==Problem 7== | ||
+ | Let <math>A</math> be the set of positive integer divisors of <math>2025</math>. Let <math>B</math> be a randomly selected subset of <math>A</math>. The probability that <math>B</math> is a nonempty set with the property that the least common multiple of its element is <math>2025</math> is <math>\frac{m}{n}</math>, where <math>m</math> and <math>n</math> are relatively prime positive integers. Find <math>m+n</math>. | ||
[[2025 AIME II Problems/Problem 7|Solution]] | [[2025 AIME II Problems/Problem 7|Solution]] | ||
==Problem 8== | ==Problem 8== | ||
+ | From an unlimited supply of <math>1</math>-cent coins, <math>10</math>-cent coins, and <math>25</math>-cent coins, Silas wants to find a collection of coins that has a total value of <math>N</math> cents, where <math>N</math> is a positive integer. He uses the so-called <math>\textit{greedy algorithm}</math>, successively choosing the coin of greatest value that does not cause the value of his collection to exceed <math>N</math>. For example, to get <math>42</math> cents, Silas will choose a <math>25</math>-cent coin, then a <math>10</math>-cent coin, then <math>7</math> <math>1</math>-cent coins. However, this collection of <math>9</math> coins uses more coins than necessary to get a total of <math>42</math> cents; indeed, choosing <math>4</math> <math>10</math>-cent coins and <math>2</math> <math>1</math>-cent coins achieves the same total value with only <math>6</math> coins. | ||
+ | |||
+ | In general, the greedy algorithm succeeds for a given <math>N</math> if no other collection of <math>1</math>-cent, <math>10</math>-cent, and <math>25</math>-cent coins gives a total value of <math>N</math> cents using strictly fewer coins than the collection given by the greedy algorithm. Find the number of values of <math>N</math> between <math>1</math> and <math>1000</math> inclusive for which the greedy algorithm succeeds. | ||
[[2025 AIME II Problems/Problem 8|Solution]] | [[2025 AIME II Problems/Problem 8|Solution]] | ||
− | ==Problem 9== | + | ==Problem 9== |
− | + | There are <math>n</math> values of <math>x</math> in the interval <math>0<x<2\pi</math> where <math>f(x)=\sin(7\pi\cdot\sin(5x))=0</math>. For <math>t</math> of these <math>n</math> values of <math>x</math>, the graph of <math>y=f(x)</math> is tangent to the <math>x</math>-axis. Find <math>n+t</math>. | |
− | |||
[[2025 AIME II Problems/Problem 9|Solution]] | [[2025 AIME II Problems/Problem 9|Solution]] | ||
==Problem 10== | ==Problem 10== | ||
+ | Sixteen chairs are arranged in a row. Eight people each select a chair in which to sit so that no person sits next to two other people. Let <math>N</math> be the number of subsets of <math>16</math> chairs that could be selected. Find the remainder when <math>N</math> is divided by <math>1000</math>. | ||
[[2025 AIME II Problems/Problem 10|Solution]] | [[2025 AIME II Problems/Problem 10|Solution]] | ||
==Problem 11== | ==Problem 11== | ||
− | + | Let <math>S</math> be the set of vertices of a regular <math>24</math>-gon. Find the number of ways to draw <math>12</math> segments of equal lengths so that each vertex in <math>S</math> is an endpoint of exactly one of the <math>12</math> segments. | |
[[2025 AIME II Problems/Problem 11|Solution]] | [[2025 AIME II Problems/Problem 11|Solution]] | ||
==Problem 12== | ==Problem 12== | ||
+ | Let <math>A_1A_2\dots A_{11}</math> be an <math>11</math>-sided non-convex simple polygon with the following properties: | ||
− | [[2025 AIME II Problems/Problem 12|Solution]] | + | • For every integer <math>2 \leq i \leq 10</math>, the area of <math>A_iA_1A_{i+1}</math> is <math>1</math>, |
+ | |||
+ | • For every integer <math>2 \leq i \leq 10</math>, <math>\cos(\angle A_iA_1A_{i+1})=\frac{12}{13}</math>, | ||
+ | |||
+ | • The perimeter of the <math>11</math>-gon <math>A_1A_2\dots A_{11}</math> is equal to <math>20</math>. | ||
+ | |||
+ | If <math>A_1A_2+A_1A_{11}</math> can be expressed as <math>\frac{m\sqrt{n}-p}{q}</math> where <math>m,n,p,q</math> are positive integers, <math>n</math> is not divisible by any square, and no prime divides all of <math>m</math>,<math>p</math>, and <math>q</math>. Find <math>m+n+p+q</math>. | ||
+ | |||
+ | |||
+ | [[2025 AIME II Problems/Problem 12|Solution]] | ||
==Problem 13== | ==Problem 13== | ||
+ | Let the sequence of rationals <math>x_1,x_2,\dots</math> be defined such that <math>x_1=\frac{25}{11}</math> and | ||
+ | <cmath>x_{k+1}=\frac{1}{3}\left(x_k+\frac{1}{x_k}-1\right)</cmath> for all <math>k \leq 1</math>. Then <math>x_{2025}</math> can be expressed as <math>\frac{m}{n}</math> for relatively prime positive integers <math>m</math> and <math>n</math>. Find the remainder when <math>m+n</math> is divided by <math>1000</math>. | ||
− | [[2025 AIME II Problems/Problem 13|Solution]] | + | [[2025 AIME II Problems/Problem 13|Solution]] |
==Problem 14== | ==Problem 14== | ||
+ | Let <math>{\triangle ABC}</math> be a right triangle with <math>\angle A = 90^\circ</math> and <math>BC = 38.</math> There exist points <math>K</math> and <math>L</math> inside the triangle such<cmath>AK = AL = BK = CL = KL = 14.</cmath>The area of the quadrilateral <math>BKLC</math> can be expressed as <math>n\sqrt3</math> for some positive integer <math>n.</math> Find <math>n.</math> | ||
[[2025 AIME II Problems/Problem 14|Solution]] | [[2025 AIME II Problems/Problem 14|Solution]] | ||
==Problem 15== | ==Problem 15== | ||
− | + | There are exactly three positive real numbers <math>k</math> such that the function | |
+ | <cmath>f(x)=\frac{(x-18)(x-72)(x-98)(x-k)}{x}</cmath> defined over the positive real numbers achieves its minimum value at exactly two positive real numbers <math>x</math>. Find the sum of these three values of <math>k</math>. | ||
[[2025 AIME II Problems/Problem 15|Solution]] | [[2025 AIME II Problems/Problem 15|Solution]] |
Latest revision as of 14:23, 23 February 2025
2025 AIME II (Answer Key) | AoPS Contest Collections • PDF | ||
Instructions
| ||
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 |
Contents
Problem 1
Six points and
lie in a straight line in that order. Suppose that
is a point not on the line and that
,
,
,
,
,
, and
Find the area of
Problem 2
Find the sum of all positive integers such that
divides the product
Problem 3
Four unit squares form a grid. Each of the
unit line segments forming the sides of the squares is colored either red or blue in such a way that each unit square has
red sides and
blue sides. One example is shown below (red is solid, blue is dashed). Find the number of such colorings.
Problem 4
The productis equal to
where
and
are relatively prime positive integers. Find
Problem 5
Suppose has angles
and
Let
and
be the midpoints of sides
and
respectively. The circumcircle of
intersects
and
at points
and
respectively. The points
and
divide the circumcircle of
into six minor arcs, as shown. Find
where the arcs are measured in degrees.
Problem 6
Circle with radius
centered at point
is internally tangent at point
to circle
with radius
. Points
and
lie on
such that
is a diameter of
and
. The rectangle
is inscribed in
such that
,
is closer to
than to
, and
is closer to
than to
, as shown. Triangles
and
have equal areas. The area of rectangle
is
, where
and
are relatively prime positive integers. Find
.
Problem 7
Let be the set of positive integer divisors of
. Let
be a randomly selected subset of
. The probability that
is a nonempty set with the property that the least common multiple of its element is
is
, where
and
are relatively prime positive integers. Find
.
Problem 8
From an unlimited supply of -cent coins,
-cent coins, and
-cent coins, Silas wants to find a collection of coins that has a total value of
cents, where
is a positive integer. He uses the so-called
, successively choosing the coin of greatest value that does not cause the value of his collection to exceed
. For example, to get
cents, Silas will choose a
-cent coin, then a
-cent coin, then
-cent coins. However, this collection of
coins uses more coins than necessary to get a total of
cents; indeed, choosing
-cent coins and
-cent coins achieves the same total value with only
coins.
In general, the greedy algorithm succeeds for a given if no other collection of
-cent,
-cent, and
-cent coins gives a total value of
cents using strictly fewer coins than the collection given by the greedy algorithm. Find the number of values of
between
and
inclusive for which the greedy algorithm succeeds.
Problem 9
There are values of
in the interval
where
. For
of these
values of
, the graph of
is tangent to the
-axis. Find
.
Problem 10
Sixteen chairs are arranged in a row. Eight people each select a chair in which to sit so that no person sits next to two other people. Let be the number of subsets of
chairs that could be selected. Find the remainder when
is divided by
.
Problem 11
Let be the set of vertices of a regular
-gon. Find the number of ways to draw
segments of equal lengths so that each vertex in
is an endpoint of exactly one of the
segments.
Problem 12
Let be an
-sided non-convex simple polygon with the following properties:
• For every integer , the area of
is
,
• For every integer ,
,
• The perimeter of the -gon
is equal to
.
If can be expressed as
where
are positive integers,
is not divisible by any square, and no prime divides all of
,
, and
. Find
.
Problem 13
Let the sequence of rationals be defined such that
and
for all
. Then
can be expressed as
for relatively prime positive integers
and
. Find the remainder when
is divided by
.
Problem 14
Let be a right triangle with
and
There exist points
and
inside the triangle such
The area of the quadrilateral
can be expressed as
for some positive integer
Find
Problem 15
There are exactly three positive real numbers such that the function
defined over the positive real numbers achieves its minimum value at exactly two positive real numbers
. Find the sum of these three values of
.
See also
2025 AIME II (Problems • Answer Key • Resources) | ||
Preceded by 2025 AIME I |
Followed by 2026 AIME I | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
All AIME Problems and Solutions |
- American Invitational Mathematics Examination
- AIME Problems and Solutions
- Mathematics competition resources
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.