IMO 1970 Longlist

IMO 1970 Longlist — 47 problems.

47 items

IMO 1970 Longlist

47 problems · Source: IMO Compendium

Problem Origin Statement
AUT1 AUT Prove that
AUT2 AUT Prove that the two last digits of 999 and 9999
AUT3 AUT Prove that for a, b \inN, a!b! divides (a + b)!.
AUT4 AUT Solve the system of equations
AUT5 AUT Prove that
BEL6 BEL Prove that the equation in x
BEL7 BEL Let ABCD be any quadrilateral. A square is constructed on
BEL9 BEL If n is even, prove that
BEL10 BEL Let A, B, C be angles of a triangle. Prove that
BEL11 BEL Let ABCD and A′B′C′D′ be two squares in the same plane and
BUL12 BUL Let x1, x2, x3, x4, x5, x6 be given integers, not divisible by 7.
BUL13 BUL A triangle ABC is given. Each side of ABC is divided into equal
BUL14 BUL Let \alpha + \beta + \gamma = \pi. Prove that
BUL15 BUL Given a triangle ABC, let R be the radius of its circumcir-
BUL16 BUL Show that the equation
CZS19 CZS Let n > 1 be a natural number, a \geq1 a real number, and
CZS21 CZS Find necessary and sufficient conditions on given positive num-
FRA23 FRA Let E be a finite set, PE the family of its subsets, and f a
FRA24 FRA Let n and p be two integers such that 2p \leqn. Prove the
FRA25 FRA Suppose that f is a real function defined for 0 \leqx \leq1 having
FRA26 FRA Consider a finite set of vectors in space {a1, a2, . . . , an} and
FRA27 FRA Find a natural number n such that for all prime numbers p, n
GDR28 GDR A set G with elements u, v, w, . . . is a group if the following
GDR29 GDR Prove that the equation 4x+6x = 9x has no rational solutions.
GDR31 GDR Prove that for any triangle with sides a, b, c and area P the
NET32 NET Let there be given an acute angle \angleAOB = 3\alpha, where OA =
NET33 NET The vertices of a given square are clockwise lettered A, B, C, D.
NET34 NET In connection with a convex pentagon ABCDE we consider
NET35 NET Find for every value of n a set of numbers p for which the fol-
NET36 NET Let x, y, z be nonnegative real numbers satisfying
NET37 NET Solve the set of simultaneous equations
POL38 POL Find the greatest integer A for which in any permutation of
POL40 POL Let ABC be a triangle with angles \alpha, \beta, \gamma commensurable with
POL41 POL Let a cube of side 1 be given. Prove that there exists a point
ROM43 ROM Prove that the equation
ROM44 ROM If a, b, c are side lengths of a triangle, prove that
ROM45 ROM Let M be an interior point of tetrahedron V ABC. Denote
ROM46 ROM Given a triangle ABC and a plane \pi having no common points
ROM47 ROM Given a polynomial
ROM48 ROM Let a polynomial p(x) with integer coefficients take the value
SWE49 SWE For n \inN, let f(n) be the number of positive integers k \leqn
SWE50 SWE The area of a triangle is S and the sum of the lengths of its
SWE51 SWE Let p be a prime number. A rational number x, with 0 < x < 1,
SWE53 SWE A square ABCD is divided into (n −1)2 congruent squares,
USS55 USS A turtle runs away from an UFO with a speed of 0.2 m/s. The
USS56 USS A square hole of depth h whose base is of length a is given.
USS57 USS Let the numbers 1, 2, . . . , n2 be written in the cells of an n \times n