MathDB
2008 El Salvador Correspondence / Qualifying NMO VIII

Source:

October 16, 2021
algebrageometrycombinatoricsnumber theoryel salvador NMO

Problem Statement

p1. Figures 00, 1 1, 22 and 33 consist of 11, 55, 1313 and 2525 squares. If you continue with this scheme, define how many squares figure 100100 has. https://cdn.artofproblemsolving.com/attachments/2/1/ffc1675513e285e51881b6ef54aa5fb2640605.png
p2. The figure shows 55 scales with objects and the total weights in each of them: https://cdn.artofproblemsolving.com/attachments/d/5/4408d9f3ae40b5fcb4c5e30941b699bffd65ed.png One of the scales malfunctions and the other 44 indicate the correct weight. Determine which scale is malfunctioning and enter the weights of each object : \blacklozenge, \bullet, \Box
p3. The positive real numbers aa and b b satisfy the relation ab=abab = a-b. Find the value of a/b+b/aaba/b + b/a - ab.
p4. Let ABCDABCD be a square of area 1 1. Let PP and QQ be points outside the square such that the triangles ABPABP and BCQBCQ are equilateral. Find the area of the triangle PBQPBQ.
p5. Place different natural numbers greater than 1 1 in the boxes, so that each number is a multiple of the number written in the box to its left, and that the sum of the five numbers is 517517. https://cdn.artofproblemsolving.com/attachments/6/3/8257ecdaac09b73186e9c84b26668d5b26e413.png