The Southeast Asia Mathematical Olympiad (SEAMO) is an international Math Olympiad competition that originated in Singapore and was founded by Mr. Terry Chew in 2016 in 8 Southeast Asian Countries. Since then, it is growing its popularity around the world. In 2019 it was recognized by 18 countries. In 2020 total number of participating countries increased to 22, including students from Indonesia, Brazil, China, Newzealand, and Taiwan students enrolled in SEAMO 2022-23.

**Problem and Solution SEAMO 2021 paper B**. Soal ini bersumber dari seamo-official.org

1. Find the value of ๐ in

\(1 + 2 + 3 + 4 + โฏ + ๐ = 253\)

(A) 20

(B) 21

(C) 22

(D) 23

(E) 24

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) 19

(B) 27

(C) 47

(D) 57

(E) None of the above

3. Find, in ๐ยฒ , the area of the shaded region.

(A) 17

(B) 19

(C) 35

(D) 54

(E) None of the above

4. Evaluate

\(100 โ 99 + 98 โ 97 + 96 โ 95 + โฏ

+ 4 โ 3 + 2 โ 1\)

(A) 48

(B) 49

(C) 50

(D) 99

(E) 100

5. A new operation is defined as

๐ โป ๐ = (๐ + ๐) รท 2

Find the value of 3 โป (6 โป 8)

(A) 3

(B) 4

(C) 5

(D) 6

(E) 7

6. A whole number ๐ 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, which still gives a value of 6. Find the value of ๐.

(A) 10

(B) 11

(C) 12

(D) 13

(E) 14

7. Some teenagers are being questioned by the traffic police.

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) Both Adrian and Ben can drive

(B) Both Ben and Chris can drive

(C) Only Adrian can drive

(D) Ben cannot drive

(E) Chris cannot drive

8. There are 19 chickens, ducks and goats on a farm. The farmer counted 56 animal legs altogether. How many goats are there?

(A) 10

(B) 9

(C) 8

(D) 7

(E) 6

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) 36

(B) 47

(C) 49

(D) 51

(E) 53

10. Find the number of ways for an insect to climb from Point ๐ด to Point ๐ถ , by passing through Point ๐ต.

(A) 8

(B) 9

(C) 10

(D) 11

(E) 12