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2006 DMM Team Round - Duke Math Meet

Source:

January 14, 2022
algebrageometrycombinatoricsnumber theoryDMM

Problem Statement

p1. What is the smallest positive integer xx such that 1x<1201112006\frac{1}{x} <\sqrt{12011} - \sqrt{12006}?
p2. Two soccer players run a drill on a 100100 foot by 300300 foot rectangular soccer eld. The two players start on two different corners of the rectangle separated by 100100 feet, then run parallel along the long edges of the eld, passing a soccer ball back and forth between them. Assume that the ball travels at a constant speed of 5050 feet per second, both players run at a constant speed of 3030 feet per second, and the players lead each other perfectly and pass the ball as soon as they receive it, how far has the ball travelled by the time it reaches the other end of the eld?
p3. A trapezoid ABCDABCD has ABAB and CDCD both perpendicular to ADAD and BC=AB+ADBC =AB + AD. If AB=26AB = 26, what is CD2AD+CD\frac{CD^2}{AD+CD} ?
p4. A hydrophobic, hungry, and lazy mouse is at (0,0)(0, 0), a piece of cheese at (26,26)(26, 26), and a circular lake of radius 525\sqrt2 is centered at (13,13)(13, 13). What is the length of the shortest path that the mouse can take to reach the cheese that also does not also pass through the lake?
p5. Let a,ba, b, and cc be real numbers such that a+b+c=0a + b + c = 0 and a2+b2+c2=3a^2 + b^2 + c^2 = 3. If a5+b5+c50a^5 + b^5 + c^5\ne 0, compute (a3+b3+c3)(a4+b4+c4)a5+b5+c5\frac{(a^3+b^3+c^3)(a^4+b^4+c^4)}{a^5+b^5+c^5}.
p6. Let SS be the number of points with integer coordinates that lie on the line segment with endpoints (222,444)\left( 2^{2^2}, 4^{4^4}\right) and (444,0)\left(4^{4^4}, 0\right). Compute log2(S1)\log_2 (S - 1).
p7. For a positive integer nn let f(n)f(n) be the sum of the digits of nn. Calculate f(f(f(22006)))f(f(f(2^{2006})))
p8. If a1,a2,a3,a4a_1, a_2, a_3, a_4 are roots of x42006x3+11x+11=0x^4 - 2006x^3 + 11x + 11 = 0, find a13+a23+a33+a43|a^3_1 + a^3_2 + a^3_3 + a^3_4|.
p9. A triangle ABCABC has MM and NN on sides BCBC and ACAC, respectively, such that AMAM and BNBN intersect at PP and the areas of triangles ANPANP, APBAPB, and PMBPMB are 55, 1010, and 88 respectively. If RR and SS are the midpoints of MCMC and NCNC, respectively, compute the area of triangle CRSCRS.
p10. Jack's calculator has a strange button labelled ''PS.'' If Jack's calculator is displaying the positive integer nn, pressing PS will cause the calculator to divide nn by the largest power of 22 that evenly divides nn, and then adding 1 to the result and displaying that number. If Jack randomly chooses an integer kk between 1 1 and 10231023, inclusive, and enters it on his calculator, then presses the PS button twice, what is the probability that the number that is displayed is a power of 22?
PS. You should use hide for answers. Collected [url=https://artofproblemsolving.com/community/c5h2760506p24143309]here.