IMO 1988 Shortlist

IMO 1988 Shortlist — 31 problems. 31 problems.

31 items

IMO 1988 Shortlist

31 problems · Source: IMO Compendium

Problems

# Origin Problem
1 BUL An integer sequence is defined by
2 BUL Let n be a positive integer. Find the number of odd coefficients
3 CAN The triangle ABC is inscribed in a circle. The interior bi-
4 CZS An n \times n chessboard (n \geq2) is numbered by the numbers
5 CZS Let n be an even positive integer. Let A1, A2, . . . , An+1 be
6 CZS In a given tetrahedron ABCD let K and L be the centers of
7 FRA Let a be the greatest positive root of the equation x3−3x2+1 =
8 FRA Let u1, u2, . . . , um be m vectors in the plane, each of length
9 FRG Let a and b be two positive integers such that ab+1 divides
10 GDR Let N = {1, 2, . . ., n}, n \geq2. A collection F = {A1, . . . , At}
11 GDR The lock on a safe consists of three wheels, each of which may
12 GRE In a triangle ABC, choose any points K \inBC, L \inAC,
13 GRE In a right-angled triangle ABC, let AD be the altitude
14 HUN For what values of n does there exist an n \times n array of entries
15 ICE Let ABC be an acute-angled triangle. Three lines LA, LB,
16 IRE Show that the solution set of the inequality
17 ISR In the convex pentagon ABCDE, the sides BC, CD, DE have
18 LUX Consider two concentric circles of radii R and r (R > r)
19 MEX Let f(n) be a function defined on the set of all positive integers
20 MON Find the least natural number n such that if the set
21 POL Forty-nine students solve a set of three problems. The score for
22 KOR Let p be the product of two consecutive integers greater than
23 SIN Let Q be the center of the inscribed circle of a triangle ABC.
24 SWE Let {ak}\infty
25 GBR A positive integer is called a double number if its decimal rep-
26 GBR A function f defined on the positive integers (and taking
27 GBR The triangle ABC is acute-angled. Let L be any line in the
28 GBR The sequence {an} of integers is defined by a1 = 2, a2 = 7,
29 USA A number of signal lights are equally spaced along a one-way
30 USS A point M is chosen on the side AC of the triangle ABC in
31 USS Around a circular table an even number of persons have a