Indonesia Juniors 2020 day 1 KSN SMP
Source:
November 10, 2021
algebrageometrycombinatoricsnumber theoryindonesia juniors
Problem Statement
p1. Let be the diameter of the circle and is a point outside the circle. The lines and are tangent to the circles at points and . The lines is perpendicular on line at . Line intersects at . If and , find .
p2. There is a meeting consisting of seats attended by invited guests. If each invited guest must be limited to at least chair, then determine the number of arrangements.
p3. In the crossword puzzle, in the following crossword puzzle, each box can only be filled with numbers from to .
https://cdn.artofproblemsolving.com/attachments/2/e/224b79c25305e8ed9a8a4da51059f961b9fbf8.png
Across:
1. Composite factor of
3. Non-polyndromic numbers
5. , with and primesDown:
1. and , and primes
2. multiple of
4. , with and primes
p4. Given a function and a function , so that it fulfills the following figure:
https://cdn.artofproblemsolving.com/attachments/b/9/fb8e4e08861a3572412ae958828dce1c1e137a.png
Find the number of values of , such that .
p5. In a garden that is rectangular in shape, there is a watchtower in each corner and in the garden there is a monitoring tower. Small areas will be made in the shape of a triangle so that the corner points are towers (free of monitoring and/or supervisory towers). Let be the number of small areas created if there are control towers and monitoring towers.
a. Find the values of , , , and
b. Find the general formula with and natural numbers .