SEAMO 2022 — Paper C — Grade 5–6

Question 1

Given $A:B=6:5$, $B:C=4:3$, $C:D=5:6$ and $A=120$, find $D$.

$75$
$80$
$90$
$100$
$120$

Question 2

Subtract $5$ from $7n$, divide the result by $5$, then add $9$. The final result is $22$. Find the integer $n$.

$7$
$8$
$9$
$10$
$11$

Question 3

For different integers $P,Q$, define $P*Q=PQ/2$. Find $3*(6*8)$.

$34$
$36$
$38$
$40$
$42$

Question 4

Which has the largest value among $2^{415},3^{249},5^{166}$?

$5^{166}$
$2^{415}$
$3^{249}$
$5^{166}$ and $2^{415}$
All equal

Question 5

Find the number of shortest paths from $A$ to $B$ on the staircase grid. Only right and up movements are permitted.

Question illustration

$720$
$880$
$920$
$950$
$1000$

Question 6

Twelve points lie on a circle. How many triangles can be formed by choosing three of them?

$150$
$180$
$210$
$220$
$240$

Question 7

Dr Soe drives from Yangon to Mandalay. At $90$ km/h he would arrive at $2{:}00$ pm; at $105$ km/h he would arrive at $1{:}00$ pm. Find the distance.

$620$
$625$
$630$
$635$
$640$

Question 8

Dean and Pong alternately take $1,2,$ or $3$ marbles from a box of $81$. Whoever takes the last wins. Dean starts. What first move guarantees his win?

Take one
Take two
Take three
The starter always wins
No winning strategy

Question 9

Tevbot takes $1,2,$ or $3$ matchsticks per move from ten matchsticks. How many ordered sequences remove them all?

$274$
$275$
$276$
$280$
$295$

Question 10

Fifty notes of denominations $1,2,5$ dollars total $116$ dollars. There are two more one-dollar than two-dollar notes. How many five-dollar notes?

$9$
$10$
$11$
$12$
$13$

Question 11

Find the units digit of $3^{2020}+4^{2021}+5^{2022}$.

Question 12

Find the remainder of $34\times37\times41\times43$ upon division by $13$.

Question 13

A square of side $14$ cm contains an inscribed circle and a quadrant, as shown. Find the dark shaded region, using $\pi=22/7$.

Question illustration

$28.5$
$31.5$
$37.5$
$40.5$
$42.5$

Question 14

How many triangles are in the figure?

Question illustration

$43$
$44$
$45$
$46$
$47$

Question 15

A three-digit locker code is guessed as $954$, $358$, and $214$ by three people. Each guess has exactly one digit correct in its position. Which code could it be?

$954$
$254$
$258$
$918$
$914$

Question 16

Evaluate $12359\times12486-12489\times12356$.

$360$
$390$
$420$
$450$
$480$

Question 17

Nuggets are sold only in packets of five or eight. What is the largest number of nuggets that cannot be bought?

$13$
$17$
$19$
$27$
$29$

Question 18

Evaluate $(46-\frac18)\frac18+(43-\frac18)\frac18+\cdots+(1-\frac18)\frac18$.

$44\frac{25}{64}$
$45\frac{27}{64}$
$46\frac3{32}$
$46\frac9{16}$
$46\frac34$

Question 19

Michelle and Lenny finish a project together in twenty-four days. Michelle working alone six days followed by Lenny alone four days would complete $1/5$. How many days would Michelle need alone?

$12$
$24$
$30$
$50$
$60$

Question 20

Grade A durians cost $12$ dollars each, Grade B $22$ dollars each. Mr Tan buys some of both for $126$ dollars. How many Grade A durians?