MathDB
Indonesia Juniors 2014 day 2 OSN SMP

Source:

November 4, 2021
algebrageometrynumber theorycombinatoricsindonesia juniors

Problem Statement

p1. Nurbaya's rectangular courtyard will be covered by a number of paving blocks in the form of a regular hexagon or its pieces like the picture below. The length of the side of the hexagon is 12 12 cm. https://cdn.artofproblemsolving.com/attachments/6/1/281345c8ee5b1e80167cc21ad39b825c1d8f7b.png Installation of other paving blocks or pieces thereof so that all fully covered page surface. To cover the entire surface The courtyard of the house required 603603 paving blocks. How many paving blocks must be cut into models A,B,CA, B, C, and DD for the purposes of closing. If 1717 pieces of model AA paving blocks are needed, how many the length and width of Nurbaya's yard? Count how much how many pieces of each model B,CB, C, and DD paving blocks are used.
p2. Given the square PQRSPQRS. If one side lies on the line y=2xāˆ’17y = 2x - 17 and its two vertices lie on the parabola y=x2y = x^2, find the maximum area of possible squares PQRSPQRS .
p3. In the triangular pyramid T.ABCT.ABC, the points E,F,GE, F, G, and HH lie at , respectively ABAB, ACAC, TCTC, and TBTB so that EA:EB=FA:FC=HB:HT=GC:GT=2:1EA : EB = FA : FC = HB : HT = GC : GT = 2:1. Determine the ratio of the volumes of the two halves of the divided triangular pyramid by the plane EFGHEFGH.
p4. We know that xx is a non-negative integer and yy is an integer. Define all pair (x,y)(x, y) that satisfy 1+2x+22x+1=y21 + 2^x + 2^{2x + 1} = y^2.
p5. The coach of the Indonesian basketball national team will select the players for become a member of the core team. The coach will judge five players A,B,C,DA, B, C, D and EE in one simulation (or trial) match with total time 8080 minute match. At any time there is only one in five players that is playing. There is no limit to the number of substitutions during the match. Total playing time for each player A,BA, B, and CC are multiples of 55 minutes, while the total playing time of each players DD and EE are multiples of 77 minutes. How many ways each player on the field based on total playing time?