Paper B 2021 [PDF]

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QUESTIONS 1 TO 10 ARE WORTH 3 MARKS EACH



4. Evaluate 100 − 99 + 98 − 97 + 96 − 95 + ⋯ +4−3+2−1



1. Find the value of 𝑚 in (A) (B) (C) (D) (E)



1 + 2 + 3 + 4 + ⋯ + 𝑚 = 253 (A) (B) (C) (D) (E)



20 21 22 23 24



5. A new operation is defined as 𝑚 ※ 𝑛 = (𝑚 + 𝑛) ÷ 2



2. Shawn and Matthew have 76 books altogether. The number of books Shawn has is 3 times the number of books of Matthew has. How many books does Shawn have? (A) (B) (C) (D) (E)



48 49 50 99 100



Find the value of 3 ※ (6 ※ 8) (A) (B) (C) (D) (E)



19 27 47 57 None of the above



3 4 5 6 7



6. A whole number 𝑛 is multiplied by 6. 6 is then added to this product, after which the sum is divided by 6. Finally, 6 is subtracted from the quotient, 3. Find, in 𝑚2 , the area of the shaded which still gives a value of 6. Find the region. value of 𝑛. 9m



1m



(A) (B) (C) (D) (E)



1m



(A) (B) (C) (D) (E)



6m



17 19 35 54 None of the above



SEAMO 2021 Paper B



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10 11 12 13 14



7. Some teenagers are being questioned 10. Find the number of ways for an insect by the traffic police. to climb from Point 𝐴 to Point 𝐶 , by passing through Point 𝐵. Adrian: I have a driving license. Ben: I do not know how to drive. Chris: Ben does not know how to drive. Given that only one person is telling the truth, which of the following conclusions can we make? (A) (B) (C) (D) (E)



Both Adrian and Ben can drive Both Ben and Chris can drive Only Adrian can drive Ben cannot drive Chris cannot drive



(A) (B) (C) (D) (E)



8. There are 19 chickens, ducks and goats on a farm. The farmer counted 56 animal legs altogether. How many goats are there? (A) (B) (C) (D) (E)



QUESTIONS 11 TO 20 ARE WORTH 4 MARKS EACH 11. The average of 5 whole numbers 20. When one of the numbers changed to 18, the new average now 18. What is the original value that number?



10 9 8 7 6



(A) (B) (C) (D) (E)



9. The teacher wanted to distribute 100 apples as fairly as possible to the children at a nursery. At least one of the children received 3 apples. What could be the maximum number of children at the nursery? (A) (B) (C) (D) (E)



8 9 10 11 12



is is is of



26 28 30 32 34



36 47 49 51 53



2



SEAMO 2021 Paper B



12. The fruit seller is packing oranges 15. Find ∠𝑎 + ∠𝑏 + ∠𝑐 + ∠𝑑. into some bags. If he packs 5 oranges into each bag, he has 14 oranges leftover. If he packs 7 oranges into each bag, he will need another 2 bags. How many oranges does the fruit seller have? (A) (B) (C) (D) (E)



76 78 80 82 84



(A) (B) (C) (D) (E)



13. Find the value of (



(A) (B) (C) (D) (E)



1 1 1 + + +⋯ 1×2 2×3 3×4 1 + ) × 2022 2021 × 2022



180∘ 270∘ 360∘ 450∘ None of the above



16. Find the missing number 40 45 29 ( )



2020 2021 2022 2023 None of the above



(A) (B) (C) (D) (E)



24 19 5 15



8 13 12 17



49 50 51 52 53



14. Find the value of ̅̅̅̅ 𝐴𝐵 in 17. Find the remainder when − (A) (B) (C) (D) (E)



𝐴 𝐵



𝐵 𝐶 𝐶 𝐴 𝐴 𝐵



555 … 55 ⏟ 2021 5's



is divided by 13.



32 38 44 54 65



SEAMO 2021 Paper B



(A) (B) (C) (D) (E)



3



5 3 9 4 6



18. 4 triangles are formed using 9 line 20. How many rectangles are there in the segments of equal lengths. If 4 beads figure? are to be put along each line segment at equal intervals, how many beads will there be altogether?



(A) (B) (C) (D) (E)



(A) (B) (C) (D) (E)



20 21 22 24 25



22 24 25 26 27



QUESTIONS 21 TO 25 ARE WORTH 6 MARKS EACH 19. Javier was walking home using the 21. In Mathematics, path indicated by the arrows. 12 = 1 × 1 = 1 22 = 2 × 2 = 4 32 = 3 × 3 = 9 … …



120 m



70 m



It is also observed that 22 = 12 + 3 32 = 22 + 5 42 = 32 + 7 52 = 42 + 9 … … 2 21 = 𝑎2 + 𝑏



What was the total distance, in metres, he had covered by the time he reached home? (A) (B) (C) (D) (E)



70 95 120 190 None of the above



Find the value of (𝑎 + 𝑏).



4



SEAMO 2021 Paper B



22. The figure shows a number pattern 24. Mdm Yee has 10 apples to give to her within an array of hexagons. In the 3 children. Each child must get at middle, there is only one dot. There least one apple. are 6 dots on the 1st hexagon. There are 12 and 18 dots on the 2 nd and How many ways are there to do so? 3rd hexagons, respectively. How many dots are there in the 49 th 25. Megan was walking along a straight hexagon? road. She met an oncoming car and she asked the driver, “Did you overtake a cyclist just now?” “Yes, 10 minutes ago,” the driver replied. After walking for another 10 minutes, Megan met the cyclist. Given that the cyclist’s speed was 4 times Megan’s walking speed, how many times of Megan’s speed was the driver’s speed?



23. There are 1, 4 and 10 cubes in Figures 1, 2 and 3, respectively.



End of Paper Fig 1



Fig 2



Fig 3 How many cubes are there altogether in Figures 1 to 5?



SEAMO 2021 Paper B



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