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2022 Fryer Contest
(Grade 9)

Tuesday, April 12, 2022
(in North America and South America)

Wednesday, April 13, 2022
(outside of North American and South America)

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©2022 University of Waterloo

Instructions

Time: 75 minutes

Number of Questions: 4
Each question is worth 10 marks.

Calculating devices are allowed, provided that they do not have any of the following features: (i) internet access, (ii) the ability to communicate with other devices, (iii) information previously stored by students (such as formulas, programs, notes, etc.), (iv) a computer algebra system, (v) dynamic geometry software.

Parts of each question can be of two types:

  1. SHORT ANSWER parts indicated by Lightbulb
  2. FULL SOLUTION parts indicated by Full Solution

WRITE ALL ANSWERS IN THE ANSWER BOOKLET PROVIDED.


Do not discuss the problems or solutions from this contest online for the next 48 hours.
The name, grade, school and location, and score range of some top-scoring students will be published on our website, cemc.uwaterloo.ca. In addition, the name, grade, school and location, and score of some top-scoring students may be shared with other mathematical organizations for other recognition opportunities.
NOTE:
  1. Please read the instructions for the contest.
  2. Write all answers in the answer booklet provided.
  3. For questions marked Lightbulb, place your answer in the appropriate box in the answer booklet and show your work.
  4. For questions marked Full Solution, provide a well-organized solution in the answer booklet. Use mathematical statements and words to explain all of the steps of your solution. Work out some details in rough on a separate piece of paper before writing your finished solution.
  5. Diagrams are not drawn to scale. They are intended as aids only.
  6. While calculators may be used for numerical calculations, other mathematical steps must be shown and justified in your written solutions, and specific marks may be allocated for these steps. For example, while your calculator might be able to find the x-intercepts of the graph of an equation like y=x3−x, you should show the algebraic steps that you used to find these numbers, rather than simply writing these numbers down.

Questions

  1. In a game, a player throws a ball at a target. If they hit the target, then 7 points are added to their score. If they miss the target, then 3 points are subtracted from their score. A player’s score begins at 0, and it is possible for a player to have a negative score.

    1. Lightbulb What is Shane’s score after 6 throws if 4 of the throws are hits and 2 of the throws are misses?

    2. Lightbulb After exactly h hits and 6 misses, Susan’s score is 59. What is the value of h?

    3. Full Solution After exactly 20 throws, Souresh’s score is greater than 85 and less than 105. If exactly m of these throws are misses, determine all possible values of the positive integer m.

    1. Lightbulb Two identical rectangles, ABCD and EFGH, each with area 13 cm2, overlap as shown.

      The vertices of the first rectangle, starting with the top left vertex and moving clockwise are A, D, C and B. The vertices of the second rectangle, starting with the top left vertex and moving clockwise are E, H, G and F.  The second rectangle is placed such that vertices E and F are on sides AD and BC, respectively, of the first rectangle.

      The area of the overlapped region, rectangle EFCD, is 5 cm2. What is the area of rectangle ABGH?

    2. Full Solution Two identical right-angled triangles, JKL and MLK, overlap along side KL, as shown.

      Sides JL and MK intersect at N. The area of the overlapped region, â–³KLN, is equal to half of the area of â–³JKL. The area of the figure JKLMN is 48 cm2. If JK=6 cm, determine the length of KL.

    3. Full Solution Rectangle PQRS and â–³PQT overlap so that R lies on QT, and RS intersects PT at U, as shown.

      The area of rectangle PQRS is 108 cm2, and the area of â–³PQT is 81 cm2. If the area of the figure PQTUS is 117 cm2, determine the area of the overlapped region, PQRU.

  2. If an integer n is written as a product of prime numbers, this product (known as its prime factorization) can be used to determine the number of positive factors of n. For example, the prime factorization of 28=2×2×7=22×71. The positive factors of 28 are: 28=22×7114=21×717=20×714=22×702=21×701=20×70 Each positive factor includes 2, 1 or 0 twos, 1 or 0 sevens, and no other prime numbers. Since there are 3 choices for the number of twos, and 2 choices for the number of sevens, there are 3×2=6 positive factors of 28.

    1. Lightbulb How many positive factors does 675 have?

    2. Full Solution A positive integer n has the positive factors 9, 11, 15, and 25 and exactly fourteen other positive factors. Determine the value of n.

    3. Full Solution Determine the number of positive integers less than 500 that have the positive factors 2 and 9 and exactly ten other positive factors.

  3. Franco and Sarah play a game four times using the following rules:

    For example, if the game begins with 10 beans in one jar and 10 beans in the other jar, the sequence of play could be:

    Turn Number 1 2 3 4 5 6 7
    Number of beans removed by Franco 1 3 4 1
    Number of beans removed by Sarah 2 5 2
    Number of beans remaining in the jars 10,9 10,7 7,7 7,2 3,2 1,2 0,2

    On the next turn, Sarah cannot remove 5 beans since the greatest number of beans remaining in either jar is 2 and so after exactly 7 turns, Sarah loses and Franco wins.

    1. Lightbulb At the beginning of the first game, there are 40 beans in one jar and 0 beans in the other jar. After a total of 10 turns (5 turns for each of Franco and Sarah), what is the total number of beans left in the two jars?

    2. Lightbulb At the beginning of the second game, there are 384 beans in one jar and 0 beans in the other jar. The game ends with a winner after a total of exactly n turns. What is the value of n?

    3. Full Solution At the beginning of the third game, there are 17 beans in one jar and 6 beans in the other jar. There is a winning strategy that one player can follow to guarantee that they are the winner. Determine which player has a winning strategy and describe this strategy. (A winning strategy is a way for a player to choose a jar on each turn so that they win no matter the choices of the other player.)

    4. Full Solution At the beginning of the fourth game, there are 2023 beans in one jar and 2022 beans in the other jar. Determine which player has a winning strategy and describe this strategy.


Further Information

For students...

Thank you for writing the Fryer Contest!

Encourage your teacher to register you for the Canadian Intermediate Mathematics Contest or the Canadian Senior Mathematics Contest, which will be written in November.

Visit our website cemc.uwaterloo.ca to find

For teachers...

Visit our website cemc.uwaterloo.ca to