MathDB

Subcontests

(1)
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1999 MMPC , Part 2 = Michigan Mathematics Prize Competition

p1. The final Big 1010 standings for the 19961996 Women's Softball season were
1. Michigan 2. Minnesota З. Iowa 4. Indiana 5. Michigan State 6. Purdue 7. Northwestern 8. Ohio State 9. Penn State 10. Wisconsin (Illinois does not participate in Women's Softball.)
When you compare the 19961996 final standings (above) to the final standings for the 19991999 season, you find that the following pairs of teams changed order relative to each other from 19961996 to 19991999 (there are no ties, and no other pairs changed places):
(Iowa, Michigan State) (Indiana, Penn State) (Purdue, Wisconsin) (Iowa, Penn State) (Indiana, Wisconsin) (Northwestern, Penn State) (Indiana, Michigan State) (Michigan State, Penn State) (Northwestern, Wisconsin) (Indiana, Purdue) (Purdue, Northwestern) (Ohio State, Penn State) (Indiana, Northwestern) (Purdue, Penn State) (Ohio State, Penn State) (Indiana, Ohio State)
Determine as much as you can about the final Big 1010 standings for the 19991999 Women's Softball season. If you cannot determine the standings, explain why you do not have enough information. You must justify your answer.
p2. a) Take as a given that any expression of the form Asint+BcostA \sin t + B \cos t (A>0A>0) can be put in the form Csin(t+D)C \sin (t + D), where C>0C>0 and π/2<D<π/2-\pi /2 <D <\pi /2 . Determine CC and DD in terms of AA and BB. b) For the values of CC and DD found in part a), prove that Asint+Bcost=Csin(t+D)A \sin t + B \cos t = C \sin (t + D). c) Find the maximum value of 3sint+2cost3 \sin t +2 \cos t.
pЗ. А 66-bу-66 checkerboard is completelу filled with 1818 dominoes (blocks of size 11-bу-22). Prove that some horizontal or vertical line cuts the board in two parts but does not cut anу of the dominoes.
p4. a) The midpoints of the sides of a regular hexagon are the vertices of a new hexagon. What is the ratio of the area of the new hexagon to the area of the original hexagon? Justify your answer and simplify as much as possible. b) The midpoints of the sides of a regular nn-gon (n>2n >2) are the vertices of a new nn-gon. What is the ratio of the area of the new nn-gon to that of the old? Justify your answer and simplify as much as possible.
p5. You run a boarding house that has 9090 rooms. You have 100100 guests registered, but on any given night only 9090 of these guests actually stay in the boarding house. Each evening a different random set of 9090 guests will show up. You don't know which 9090 it will be, but they all arrive for dinner before you have to assign rooms for the night. You want to give out keys to your guests so that for any set of 9090 guests, you can assign each to a private room without any switching of keys. a) You could give every guest a key to every room. But this requires 90009000 keys. Find a way to hand out fewer than 90009000 keys so that each guest will have a key to a private room. b) What is the smallest number of keys necessary so that each guest will have a key to a private room? Describe how you would distribute these keys and assign the rooms. Prove that this number of keys is as small as possible.
PS. You should use hide for answers. Collected [url=https://artofproblemsolving.com/community/c5h2760506p24143309]here.