IMO 1994 Shortlist

IMO 1994 Shortlist — 24 problems. Algebra (5) · Combinatorics (7) · Geometry (5) · Number Theory (7).

24 items

IMO 1994 Shortlist

24 problems · Source: IMO Compendium

Algebra

# Origin Problem
A1 USA Let a0 = 1994 and an+1 =
A2 FRA Let m and n be positive integers. The set A = {a1, a2, . . . ,
A3 GBR Let S be the set of real numbers greater than −1. Find
A4 MON Let R denote the set of all real numbers and R+ the subset
A5 POL Let f(x) = x2+1

Combinatorics

# Origin Problem
C1 UKR On a 5 \times 5 board, two players alternately mark numbers on
C2 COL In a certain city, age is reckoned in terms of real numbers
C3 MCD Peter has three accounts in a bank, each with an integral
C4 EST There are n + 1 fixed positions in a row, labeled 0 to n in
C5 SWE At a round table are 1994 girls, playing a game with a deck
C6 FIN On an infinite square grid, two players alternately mark sym-
C7 BRA Prove that for any integer n \geq2, there exists a set of 2n−1

Geometry

# Origin Problem
G1 FRA A semicircle \Gamma is drawn on one side of a straight line l. C
G2 UKR ABCD is a quadrilateral with BC parallel to AD. M is the
G3 RUS A circle \omega is tangent to two parallel lines l1 and l2. A second
G4 AUS-ARM N is an arbitrary point on the bisector of \angleBAC.
G5 CYP A line l does not meet a circle \omega with center O. E is the

Number Theory

# Origin Problem
N1 BUL M is a subset of {1, 2, 3, . . ., 15} such that the product of
N2 AUS Determine all pairs (m, n) of positive integers such that
N3 FIN Find a set A of positive integers such that for any infinite
N4 FRA For any positive integer x0, three sequences {xn}, {yn}, and
N5 ROM For any positive integer k, Ak is the subset of {k+1, k+
N6 LAT Let x1 and x2 be relatively prime positive integers. For n \geq2,
N7 GBR A wobbly number is a positive integer whose digits in base 10