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2024 Beaver Computing Challenge
(Grade 7 & 8)

Questions

Part A

Beaver Robot

Story

Beaver Robot can say sentences containing exactly 3 words.

6 words in Box 1: I, YOU, BEAVERS, CAN, HELP, PLEASE. 8 words in Box 2: LOVE, LIKE, CAN, ME, HELP, NEED, YOU, US. 6 words in Box 3: HELP, SWIM, CARROTS, LOVE, YOU,
WATER.

Question

Which sentence below cannot be said by Beaver Robot?

  1. CAN YOU HELP
  2. BEAVERS CAN SWIM
  3. I LOVE YOU
  4. YOU NEED ME

Digital Image

Story

Ana created the following digital image.

A rectangular image with seven parts: top left star, top middle star, top right star, bottom left moon, bottom middle star, bottom right star, and centre star.

She did her work in stages. For the last three stages, she added the following parts of the image as shown in order from left to right.

A rectangular image with
one part: the bottom left moon. A rectangular image with
one part: the centre star. A rectangular image with
one part: the top middle star.

Now Ana has decided to undo some of her work, removing the parts added in the last three stages.

Question

Which of the following options shows the resulting picture?

  1. A rectangular image with
four parts: top left star, top right star, bottom left moon, and bottom
middle star.
  2. A rectangular image with
four parts: top left star, top right star, bottom middle star, and
centre star.
  3. A rectangular image with
four parts: top middle star, top right star, bottom left moon, and
bottom middle star.
  4. A rectangular image with
four parts: top left star, top right star, bottom middle star, and
bottom left star.

Ice Cream Shop

Story

A cool new ice cream shop with a self-service machine has opened! To place an order, you push the arrow buttons to move the robot to the square with the flavour you want and then press enter to add a scoop to the cone. After you have chosen three scoops, your order is prepared.

A description of the
diagram follows.

The robot always starts an order from the START square. For example, from left to right the sequence

left, enter, up, up and right, enter, down and right, down, enter

makes a cone where the flavours from bottom to top are

chocolate, kiwi, vanilla

Question

What flavours will be on the ice cream cone, from bottom to top, if the order uses the following sequence, from left to right?

right, enter, up and left, left, up, enter, right, down, enter

  1. vanilla, watermelon, cherry
  2. chocolate, pineapple, cherry
  3. vanilla, wiki, strawberry
  4. chocolate, cherry, vanilla

Line Drawing

Story

When Pixel tries to draw lines on graph paper, she does this by colouring in blocks of tiny squares. Each of these squares intersects the line she is trying to draw. This means she cannot always draw perfectly straight lines. An example is shown where the blocks of squares Pixel coloured do not look exactly the same as the straight diagonal line that she is trying to draw.

A description of the
diagram follows.

A pattern is formed by the shapes and sizes of blocks of squares that Pixel colours. This pattern repeats every time the line she is trying to draw passes through a corner of a square. In the example, it is always 3 vertical blocks followed by 2 vertical blocks.

Question

Pixel has started to draw the diagonal line shown and coloured in the first 8 squares as shown. If she continues drawing the line, then how will she colour the \(2 \times 3\) block of squares shown in grey?

A grid with 6 rows and 15
columns and a line from the top left corner to the bottom right corner.
The following squares are coloured in: squares 1, 2, and 3 in row 1; 4 and
5 in row 2; and 6, 7 and 8 in row 3. Squares 12, 13, and 14 in rows 5
and 6 are shaded in grey.

  1. A 2 by 3 block with the
squares in the top row coloured in.
  2. A 2 by 3 block with the
first two squares in the top row and the last square in the bottom row
coloured in.
  3. A 2 by 3 block with the
first two squares in the top row and the last two squares in the bottom
row coloured in.
  4. A 2 by 3 block with the
first square in the top row and the last two squares in the bottom row
coloured in.

Magic Garden

Story

In a magic garden, flowers can change during the night. If there is a group of at least two flowers of the same type directly beside each other, then that group of flowers transforms into a group of different flowers as follows:

A flower never changes more than once per night.

This is what the magic garden looks like one morning.

A row of five flowers, from left to right: sunflower,
sunflower, tulip, violet, tulip.

Question

What will the magic garden look like after four nights have passed?

  1. A row of five tulips.
  2. A row of four tulips on the left followed by
one rose on the right.
  3. A row of five sunflowers.
  4. A row of five flowers, from left to right:
sunflower, sunflower, tulip, violet, tulip.

Part B

Superbebras

Story

In the computer game Superbebras, the background and the illusion of motion is created using a sequence of tiles.

Tiles added to the right end of the sequence are chosen according to the rules in the diagram below. Arrows point directly from each tile to the only tile(s) that can be added immediately to the right of it.

A description of the
diagram follows.

For example, a tile immediately to the right of tile 3 can only be tile 3 or tile 2.

Question

Which of the following images is not a possible Superbebras background?

  1. Six tiles in row. From left to right, they
are tiles 2, 1, 2, 3, 3, 2.
  2. Six tiles in row. From left to right, they
are tiles 1, 2 ,1, 3, 2, 4.
  3. Six tiles in row. From left to right, they
are tiles 2, 4, 2, 2, 3, 3.
  4. Six tiles in row. From left to right, they
are tiles 3, 3, 3, 3, 3, 3.

Logs and Branches

Story

Sequences of logs and branches are represented by codes, using the following two steps.

  1. Moving from left to right in a sequence, each log or branch is represented by the number of branches to the right of it in the sequence. This gives a sequence of numbers.
  2. Then each even number in this sequence is replaced with a 0 and each odd number with a 1, to obtain its code.

Let’s look at the following sequence as an example.

From left to right: log, branch, branch, log, log, branch.

Continuing this process gives the sequence 3, 2, 1, 1, 1, 0. Its code is 101110.

Question

Which of the following sequences of logs and branches is represented by the code 11101000?

  1. branch, log, log, branch, log, log, branch, branch

  2. log, branch, log, branch, branch, branch, log, log

  3. branch, log, log, branch, branch, branch, log, log

  4. branch, log, log, branch, branch, branch, log, branch

Spices

Story

Genaro uses his balance scale to weigh the spices he sells. He uses only the following 5 weights on his scale: 1 gram, 3 grams, 9 grams, 27 grams, and 81 grams.

Genaro always puts the spices on the right side of the scale. To measure 11 grams of spices, he places his weights as shown.

A balanced scale with weights labelled 3 and 9 on the left side and a weight labelled 1 along with a jar of spices on the right side. Two weights labelled 27 and 81 sit beside the scale.

To help train new employees, Genaro creates codes for different amounts of spices. In his code, \(\text{L}\) means the weight is placed on the left side, \(\text{R}\) means the weight is placed on the right side, and \(\text{O}\) means the weight is placed off the scale. Genaro writes each code in order from the smallest weight to the largest weight. For example, the code for 11 grams of spices is \(\text{R}\text{L}\text{L}\text{O}\text{O}\), as shown.

Weight (grams) 1 3 9 27 81
Position \(\text{R}\) \(\text{L}\) \(\text{L}\) \(\text{O}\) \(\text{O}\)

Question

Among the following four codes, which measures the heaviest amount of spices?

  1. \(\text{L}\text{O}\text{R}\text{L}\text{O}\)
  2. \(\text{R}\text{R}\text{R}\text{R}\text{L}\)
  3. \(\text{L}\text{R}\text{L}\text{L}\text{O}\)
  4. \(\text{O}\text{L}\text{R}\text{L}\text{O}\)

Online Class

Story

Nine students are sitting side by side in one row in the library while their teacher conducts an online lesson from her home. The teacher sees the class from her laptop screen as shown. Each student is using a different computer, but the teacher’s screen shows who each student is sitting next to.

The screen of a laptop shows nine windows, each centred on one of nine students. A table with the name of each student, the student that is sitting to their right, and the student that is sitting to their left can be found in the Alternative Format for Online Class.

Question

Which student is sitting in the middle (5th position) of the row in the library?

  1. Raul
  2. Lee
  3. Busara
  4. Hannah

Collecting Dolls

Story

Beaver Deana enters the maze below carrying a doll of size 1. She then goes through the maze and collects dolls of different sizes, placing smaller dolls inside larger dolls.

A maze with many paths and branches. Arrows show directions of movement through the paths. Dolls of sizes 1 through 6 are placed within the maze. The entrance, where Beaver Deana is, and the exit are at opposite corners of the maze.

Deana follows the arrows and obeys the following rule whenever she encounters a doll.

Question

What is the maximum number of dolls that Deana can collect, including the size 1 doll, by the time she reaches the exit of the maze?

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

Part C

Card Art

Story

Manas creates drawings by combining some of the following images:

Image
Name cloud crown flower person pizza star sun smiley sun

Manas draws on cards following one, single, secret rule. He has created four cards that obey this rule: