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SEAMO 2027 - Paper B - SET 01 - Self-study

Question 1

SEAMO self-study edition 2027; not an official 2027 paper. Original source years are retained. 25 questions, 90 minutes; Q1–10: 3 points, Q11–20: 4 points, Q21–25: 6 points, total 100. Original response types and all subparts are preserved. Verified is an editorial convention; source defects, necessary assumptions and unresolved mathematical uncertainty are disclosed.

Each distinct letter represents a unique digit in the cryptarithm below. Find the digit represented by M.

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Question 2

There are 5 points on a rectangle as shown. How many triangles can be formed by using any 3 of these points as their vertices?

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  1. 4
  2. 5
  3. 9
  4. 10
  5. 15

Question 3

Observe the calculations: \(1+3=4=2^2\); \(1+3+5=9=3^2\); \(1+3+5+7=16=4^2\); \(1+3+5+7+9=25=5^2\). Evaluate \(1+3+5+\cdots+97+99+101+99+97+\cdots+3+1\).

Source note: The printed English block omits the first row, which is present in Vietnamese. Its square notation is printed as baseline digits such as “32”. Here the intended squares are typeset as powers, consistent with the numerical equalities.

Question 4

A whole number n is multiplied by 6. Then 6 is added to the product, the sum is divided by 6, and finally 6 is subtracted from the quotient. The result is 6. Find n.

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  1. 10
  2. 11
  3. 12
  4. 13
  5. 14

Question 5

The solid below is formed using 8 identical cubes. How does it look from above?

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  1. Diagram A
  2. Diagram B
  3. Diagram C
  4. Diagram D
  5. Diagram E

Question 6

Nick took a certain number of tests. If he scored 97 in his last test, his average would be 90. If he scored 73 in his last test, his average would be 87. How many tests did he take altogether?

Question 7

A test consists of 25 questions. A correct answer earns 4 marks and an incorrect answer deducts 2 marks. No questions were left unanswered. Gerald scored 70 marks. How many questions did he answer incorrectly?

Question 8

Find the next number in the sequence 5611, 111223, 232447, …

Use the intended simple pattern; a finite list alone does not determine a unique continuation.
  1. 232495
  2. 464793
  3. 474895
  4. 474896
  5. None of the above

Question 9

Find the remainder when the number consisting of 2021 consecutive digits 5 is divided by 13.
  1. 5
  2. 3
  3. 9
  4. 4
  5. 6

Question 10

Frank and Ben each bought some sheets of paper. If Frank and Ben used 40 and 80 sheets each day, respectively, Frank would have 500 sheets left when Ben ran out. If they used 80 and 40 sheets each day, respectively, Frank would have 20 sheets left when Ben ran out. How many sheets did they have altogether?

Question 11

There are 20 ducks, chickens and goats on a farm. They have 48 legs altogether. There are equal numbers of ducks and chickens. Find the number of goats.
  1. 2
  2. 3
  3. 4
  4. 5
  5. 6

Question 12

Jakarta and Bandung are 150 km apart via the Jakarta–Cikampek Toll Road. A car leaves Jakarta at 10:00 AM and travels towards Bandung at a constant 60 km/h. A van travels from Bandung towards Jakarta at a constant 50 km/h. At what time must the van leave to meet the car halfway between the cities?

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  1. 09:30 AM
  2. 09:35 AM
  3. 09:40 AM
  4. 09:50 AM
  5. None of the above

Question 13

A swimming pool is 30 m long. Ally and Bella start swimming towards each other from opposite ends at speeds of 2 m/s and 3 m/s, respectively. How many times do they meet in 1 minute?

Assume both swimmers turn immediately at each end and continue at their stated constant speeds. A meeting at an end of the pool counts as one meeting.

Question 14

In the diagram, the topmost layer has 60 circles. How many circles are there altogether?

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  1. 1750
  2. 1780
  3. 1830
  4. 1880
  5. None of the above

Question 15

A new operation is defined by \(a\nabla b=a+(a+1)+(a+2)+(a+3)+\cdots+(a+b)\). Find x if \(x\nabla 8=126\).
  1. 8
  2. 9
  3. 10
  4. 11
  5. 12

Question 16

Cindy’s father is 4 times as old as Cindy. Three years ago, their ages added up to 49. How old are Cindy and her father, respectively, this year?

Wording note: The source says “4 times older than”. Interpret this as “4 times as old as”, the convention intended by the source answer.

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  1. 10 and 45
  2. 11 and 44
  3. 12 and 46
  4. 9 and 36
  5. None of the above

Question 17

The diagram shows a rectangle of length 36 cm. It contains two shaded regions and 7 identical small rectangles. Find the area of one small rectangle, in square centimetres.

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  1. 98
  2. 120
  3. 144
  4. 156
  5. None of the above

Question 18

A book has 46 pages. Jane added all the page numbers but missed one, obtaining a sum of 1050. Which page number did she miss?

Question 19

The diagram shows a rectangle divided into 3 smaller rectangles and a square. The unshaded rectangle has perimeter 16 cm, and the square has area 9 cm². Find the total area of the shaded rectangles.

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Question 20

In the diagram, ABCD and DEFG are squares. Given that triangle CDH has area 8 cm², find the area of triangle AFH.

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