MathDB
2021 SMT Guts Round 5 p17-20 - Stanford Math Tournament

Source:

February 11, 2022
algebrageometrynumber theorycombinatoricsStanford Math TournamentSMT

Problem Statement

p17. Let the roots of the polynomial f(x)=3x3+2x2+x+8=0f(x) = 3x^3 + 2x^2 + x + 8 = 0 be p,qp, q, and rr. What is the sum 1p+1q+1r\frac{1}{p} +\frac{1}{q} +\frac{1}{r} ?
p18. Two students are playing a game. They take a deck of five cards numbered 11 through 55, shuffle them, and then place them in a stack facedown, turning over the top card next to the stack. They then take turns either drawing the card at the top of the stack into their hand, showing the drawn card to the other player, or drawing the card that is faceup, replacing it with the card on the top of the pile. This is repeated until all cards are drawn, and the player with the largest sum for their cards wins. What is the probability that the player who goes second wins, assuming optimal play?
p19. Compute the sum of all primes pp such that 2p+p22^p + p^2 is also prime.
p20. In how many ways can one color the 88 vertices of an octagon each red, black, and white, such that no two adjacent sides are the same color?
PS. You should use hide for answers. Collected [url=https://artofproblemsolving.com/community/c5h2760506p24143309]here.