IMO 1983 Longlist

IMO 1983 Longlist — 51 problems.

51 items

IMO 1983 Longlist

51 problems · Source: IMO Compendium

Problem Origin Statement
AUS2 AUS Seventeen cities are served by four airlines. It is noted that
AUS3 AUS (a) Given a tetrahedron ABCD and its four altitudes (i.e.,
BEL5 BEL Consider the set Q2 of points in R2, both of whose coordinates
BEL7 BEL Find all numbers x \inZ for which the number
BRA10 BRA Which of the numbers 1, 2, . . ., 1983 has the largest number of
BRA11 BRA A boy at point A wants to get water at a circular lake and
BRA12 BRA The number 0 or 1 is to be assigned to each of the n vertices
BUL13 BUL Let p be a prime number and a1, a2, . . . , a(p+1)/2 different nat-
BUL14 BUL Let l be tangent to the circle k at B. Let A be a point on k
CAN15 CAN Find all possible finite sequences {n0, n1, n2, . . . , nk} of integers
CAN17 CAN In how many ways can 1, 2, . . . , 2n be arranged in a 2 \times n
CAN18 CAN Let b \geq2 be a positive integer.
COL20 COL Let f and g be functions from the set A to the same set A.
COL21 COL Prove that there are infinitely many positive integers n for
CUB22 CUB Does there exist an infinite number of sets C consisting of 1983
FIN24 FIN Every x, 0 \leqx \leq1, admits a unique representation x =
FRG25 FRG How many permutations a1, a2, . . . , an of {1, 2, . . ., n} are
FRG26 FRG Let a, b, c be positive integers satisfying (a, b) = (b, c) = (c, a) =
GBR28 GBR Show that if the sides a, b, c of a triangle satisfy the equation
GBR29 GBR Let O be a point outside a given circle. Two lines OAB, OCD
GBR30 GBR Prove the existence of a unique sequence {un} (n = 0, 1, 2 . . .)
GBR32 GBR Let a, b, c be positive real numbers and let [x] denote the
GDR34 GDR In a plane are given n points Pi (i = 1, 2, . . . , n) and two
ISR36 ISR The set X has 1983 members. There exists a family of subsets
ISR37 ISR The points A1, A2, . . . , A1983 are set on the circumference of a
KUW38 KUW Let {un} be the sequence defined by its first two terms u0, u1
KUW39 KUW If \alpha is the real root of the equation
LUX40 LUX Four faces of tetrahedron ABCD are congruent triangles whose
LUX42 LUX Consider the square ABCD in which a segment is drawn
LUX43 LUX Given a square ABCD, let P, Q, R, and S be four variable
LUX44 LUX We are given twelve coins, one of which is a fake with a different
LUX45 LUX Let two glasses, numbered 1 and 2, contain an equal quantity
LUX46 LUX Let f be a real-valued function defined on I = (0, +\infty) and
NET47 NET In a plane, three pairwise intersecting circles C1, C2, C3 with
NET48 NET Prove that in any parallelepiped the sum of the lengths of the
POL49 POL Given positive integers k, m, n with km \leqn and nonnegative
ROM53 ROM Let a \inR and let z1, z2, . . . , zn be complex numbers of mod-
ROM55 ROM For every a \inN denote by M(a) the number of elements of
ROM56 ROM Consider the expansion
SPA57 SPA In the system of base n2 + 1 find a number N with n different
SPA59 SPA Solve the equation
SWE61 SWE Let a and b be integers. Is it possible to find integers p and q
SWE62 SWE A circle \gamma is drawn and let AB be a diameter. The point C
USA64 USA The sum of all the face angles about all of the vertices except
USA65 USA Let ABCD be a convex quadrilateral whose diagonals AC and
USA67 USA The altitude from a vertex of a given tetrahedron intersects
USA68 USA Three of the roots of the equation x4 −px3 + qx2 −rx + s = 0
USS72 USS Prove that for all x1, x2, . . . , xn \inR the following inequality
VIE73 VIE Let ABC be a nonequilateral triangle. Prove that there exist
VIE74 VIE In a plane we are given two distinct points A, B and two lines
VIE75 VIE Find the sum of the fiftieth powers of all sides and diagonals of