2018 AIME II 2卷真题及答案
Points , , and lie in that order along a straight path where the distance from to is meters. Ina runs twice as fast as Eve, and Paul runs twice as fast as Ina. The three runners start running at the same time with Ina starting at and running toward , Paul starting at and running toward , and Eve starting at and running toward . When Paul meets Eve, he turns around and runs toward . Paul and Ina both arrive at at the same time. Find the number of meters from to .
Let , , and , and for define recursively to be the remainder when ( + + ) is divided by . Find • • .
Find the sum of all positive integers such that the base- integer is a perfect square and the base- integer is a perfect cube.
In equiangular octagon , and . The self-intersecting octagon enclosed six non-overlapping triangular regions. Let be the area enclosed by , that is, the total area of the six triangular regions. Then , where and are relatively prime positive integers. Find .
Suppose that , , and are complex numbers such that , , and , where . Then there are real numbers and such that . Find .
A real number is chosen randomly and uniformly from the interval . The probability that the roots of the polynomial
are all real can be written in the form , where and are relatively prime positive integers. Find .
Triangle has side lengths , , and . Points are on segment with between and for , and points are on segment with between and for . Furthermore, each segment , , is parallel to . The segments cut the triangle into regions, consisting of trapezoids and triangle. Each of the regions has the same area. Find the number of segments , , that have rational length.
A frog is positioned at the origin of the coordinate plane. From the point , the frog can jump to any of the points , , , or . Find the number of distinct sequences of jumps in which the frog begins at and ends at .
Octagon with side lengths and is formed by removing 6-8-10 triangles from the corners of a x rectangle with side on a short side of the rectangle, as shown. Let be the midpoint of , and partition the octagon into 7 triangles by drawing segments , , , , , and . Find the area of the convex polygon whose vertices are the centroids of these 7 triangles.
Find the number of functions from to that satisfy for all in .
Find the number of permutations of such that for each with , at least one of the first terms of the permutation is greater than .
Let be a convex quadrilateral with , , and . Assume that the diagonals of intersect at point , and that the sum of the areas of and equals the sum of the areas of and . Find the area of quadrilateral .
Misha rolls a standard, fair six-sided die until she rolls -- in that order on three consecutive rolls. The probability that she will roll the die an odd number of times is , where and are relatively prime positive integers. Find .
The incircle of of is tangent to at . Let be the other intersection of with .Points and lie on and , respectively, so that is tangent to at . Assume that , and , where and are relatively prime positive integers. Find .
Find the number of functions from to the integers such that , and
for all and in .
2018AIME II 2卷答案获取方法: