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2018 Beaver Computing Challenge
(Grade 7 & 8)

Questions

Part A

Roped Trees

Story

Joni Beaver uses rope to mark groups of trees. The rope forms a very tight loop so that each tree either touches the rope or is entirely inside the loop. Below is an example where the rope touches exactly 5 trees when viewed from above.

Question

How many trees will the rope touch if the trees are arranged as follows (when viewed from above)?

  1. 4
  2. 5
  3. 6
  4. 7

Rotation Game

Story

Beavers play a simple game. The game always begins with this starting position:

In a 2 by 2 grid, the top left square is red, the top right square is green, the bottom left square is blue, and the bottom right square is yellow.

From this starting position, rotation instructions are followed. All the rotations are clockwise and one quarter of a complete turn. The possible instructions are:

For example, if the first instruction is 2R, the top-left square will be Yellow as shown below.

In a 2 by 2 grid, the top left square is yellow, the top right square is blue, the bottom left square is green, the bottom right square is red.

Question

From the starting position, what colours will the top-left square be after each of the instructions 1R, 2R, 2R, and 3R are followed in order?

  1. Red Green Blue Green Yellow
  2. Red Blue Green Blue Red
  3. Red Blue Yellow Red Green
  4. Red Red Yellow Red Blue

Beaver Graffiti

Story

Beaver graffiti consists of three different symbols: fish, flower, and leaf.

Sequences of symbols are built using two steps:

  1. One of the symbols is drawn once or twice.
  2. One of the symbols is is drawn once to the left of the current sequence and once to the right of the current sequence.

Step 1 happens first and exactly one time. Step 2 may happen any number of times. Here are five examples:

Question

Which of the following is not an example of beaver graffiti?

  1. fish fish fish
  2. flower leaf fish leaf flower
  3. leaf flower fish leaf leaf fish flower leaf
  4. leaf leaf leaf leaf fish leaf leaf leaf leaf leaf

Computer Science Museum

Story

A museum has received statues of five famous computer scientists. However, there is only room to display one statue at a time. They must decide the order in which the statues will be displayed. They come up with the following rules:

Question

What is one order in which the statues could be displayed?

  1. Turing, Hopper, Lovelace, Gates, Berners-Lee
  2. Turing, Berners-Lee, Hopper, Gates, Lovelace
  3. Turing, Gates, Hopper, Lovelace, Berners-Lee
  4. Turing, Berners-Lee, Lovelace, Hopper, Gates

Balloons

Story

Mark goes to a birthday party. A room at the party is decorated with balloons in rows: