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BBB 2022 - Grade 5 - Preliminary Round

Question 1

Find the average of these numbers: 12,39,68,45,67,20,43.
  1. 49
  2. 48
  3. 43
  4. 42

Question 2

If $2\otimes 2=2\times 4$ and $3\otimes 4=4\times 7\times 10$. Find the value of $2\otimes 5$.
  1. 10
  2. 35
  3. 30
  4. 315

Question 3

Given a rectangle with perimeter 48 cm. The length is 3 times the width. Find the length of that rectangle.
  1. 16 cm
  2. 18 cm
  3. 36 cm
  4. 24 cm

Question 4

The cost of one shirt is 6 dollars. For every 3 shirts, the customer can get a 2-dollar discount. A school needs to buy 100 shirts. At least how many dollars should they pay?
  1. 528
  2. 531
  3. 534
  4. 537

Question 5

Find the value of

$$\left(\frac{11}{2}+\frac{11}{3}+\frac{11}{4}\right)\div\left(\frac{12}{4}+\frac{12}{6}+\frac{12}{8}\right).$$
  1. $\frac{11}{3}$
  2. $\frac{11}{24}$
  3. $\frac{11}{12}$
  4. $\frac{11}{6}$

Question 6

It is known that the sum of 8 consecutive odd numbers is 160. Find the value of the largest number.
  1. 27
  2. 29
  3. 31
  4. 33

Question 7

A person can walk 350 meters in 3 minutes. Find the speed of that person.
  1. 12 km/h
  2. 6 km/h
  3. 7 km/h
  4. 11 km/h

Question 8

Find the value of $6+13+20+27+\cdots+293+300$.
  1. 6597
  2. 6579
  3. 6759
  4. 6795

Question 9

Find the value of

$$\frac 2{4\times 5}+\frac 2{5\times 6}+\frac 2{6\times 7}+\cdots+\frac 2{47\times 48}+\frac 2{48\times 49}+\frac 2{49\times 50}.$$
  1. $\frac{23}{25}$
  2. $\frac{23}{50}$
  3. $\frac{23}{100}$
  4. $\frac{23}{200}$

Question 10

Becky has 39 coins, including \$2 coins and \$5 coins worth \$147 in total. How many \$2 coins does she have?
  1. 18
  2. 23
  3. 21
  4. 16

Question 11

Find the value of $100-96+92-88+84-80+\cdots+20-16+12$.
  1. 44
  2. 56
  3. 60
  4. 92

Question 12

Use 1,5,8 and 3 without repetition. How many odd 3-digit numbers can be formed?
  1. 6
  2. 12
  3. 18
  4. 24

Question 13

If a 10-digit number $\overline{2022 A 2023 B}$ is divisible by 18, find the maximum value of A.
  1. 9
  2. 8
  3. 5
  4. 6

Question 14

Today is 13th October 2022, Thursday. Which year will satisfy that 13th October will be Wednesday for the earliest case?
  1. 2027
  2. 2028
  3. 2029
  4. 2026

Question 15

It is known that

$$x=\frac 2{4+\frac 5{3+\frac 13}}.$$

Find the value of x.
  1. $\frac4{11}$
  2. $\frac{11}8$
  3. $\frac8{11}$
  4. $\frac{11}4$

Question 16

How many 3-digit numbers that can be divisible by 2 or 5 are there?
  1. 540
  2. 630
  3. 90
  4. 450

Question 17

In a stationary store, pencils have one price and pens have another price. Two pencils and three pens cost 86 cents. But three pencils and two pens cost 84 cents. How much does one pencil cost?
  1. 34 cents
  2. 18 cents
  3. 12 cents
  4. 16 cents

Question 18

Given triangle ABC with area $200\mathrm{cm}^2$. Put point M and N on line segment AB and AC respectively such that $AM=MB$ and $NC=2\times AN$. Find the area of the shaded region.

Question illustration
  1. $20\mathrm{cm}^2$
  2. $25\mathrm{cm}^2$
  3. $33\mathrm{cm}^2$
  4. $16\mathrm{cm}^2$

Question 19

How many rectangles are there in the figure below?

Question illustration
  1. 106
  2. 114
  3. 138
  4. 118

Question 20

Numbers are drawn from 60 integers 11 to 70. At least how many numbers are drawn at random to ensure that there are two numbers whose sum is 92?
  1. 35
  2. 36
  3. 37
  4. 38