MathDB
Indonesia Juniors 2007 day 2 OSN SMP

Source:

October 31, 2021
algebrageometrynumber theorycombinatoricsindonesia juniors

Problem Statement

p1. Four kite-shaped shapes as shown below (a>ba > b, aa and bb are natural numbers less than 1010) arranged in such a way so that it forms a square with holes in the middle. The square hole in the middle has a perimeter of 1616 units of length. What is the possible perimeter of the outermost square formed if it is also known that aa and bb are numbers coprime? https://cdn.artofproblemsolving.com/attachments/4/1/fa95f5f557aa0ca5afb9584d5cee74743dcb10.png
p2. If a=3pa = 3^p, b=3qb = 3^q, c=3rc = 3^r, and d=3sd = 3^s and if p,q,rp, q, r, and ss are natural numbers, what is the smallest value of pqrsp\cdot q\cdot r\cdot s that satisfies a2+b3+c5=d7a^2 + b^3 + c^5 = d^7
3. Ucok intends to compose a key code (password) consisting of 8 numbers and meet the following conditions: i. The numbers used are 1,2,3,4,5,6,7,81, 2, 3, 4, 5, 6, 7, 8, and 99. ii. The first number used is at least 11, the second number is at least 22, third digit-at least 33, and so on. iii. The same number can be used multiple times. a) How many different passwords can Ucok compose? b) How many different passwords can Ucok make, if provision (iii) is replaced with: no numbers may be used more than once.
p 4. For any integer a,ba, b, and cc applies a×(b+c)=(a×b)+(a×c)a\times (b + c) = (a\times b) + (a\times c). a) Look for examples that show that a+(b×c)(a+b)×(a+c)a + (b\times c)\ne (a + b)\times (a + c). b) Is it always true that a+(b×c)=(a+b)×(a+c)a + (b\times c) = (a + b)\times(a + c)? Justify your answer.
p5. The results of a survey of NN people with the question whether they maintain dogs, birds, or cats at home are as follows: 5050 people keep birds, 6161 people don't have dogs, 1313 people don't keep a cat, and there are at least 7474 people who keep the most a little two kinds of animals in the house. What is the maximum value and minimum of possible value of NN ?