BD Math Olympiad 2020 Selection Questions for Primary & Junior Levels
Primary preliminary questions
1. 10 āĻŦāĻāϰ āĻŦā§āϏ⧠āĻā§āύāĻžā§ā§āĻĻā§āϰ āĻāĻā§āĻāϤāĻž āĻāĻŋāϞ 50 āϏā§āĻŽāĻŋ āĻāĻŦāĻ 20 āĻŦāĻāϰ āĻŦā§āϏ⧠āĻā§āύāĻžā§ā§āĻĻā§āϰ āĻāĻā§āĻāϤāĻž āĻšā§ā§āĻā§ 63 āϏā§āĻŽāĻŋāĨ¤ 10 āĻŦāĻāϰ⧠āĻā§āύāĻžā§ā§āĻĻā§āϰ āĻāĻā§āĻāϤāĻž āĻāϤāĻā§āĻā§ āĻŦā§ā§ā§āĻā§?
When Junayed was 10 years old, he was 50 inches tall. When he was 20 years old, Junayed was 63 inches tall. By how many inches did Junayed’s height increase in those 10 years?
2. āĻāĻŋāϤā§āϰ⧠1 āĻĨā§āĻā§ āĻļā§āϰ⧠āĻāϰ⧠āĻā§āϰāĻŽāĻŋāĻ āϏāĻāĻā§āϝāĻž āĻā§āϞ⧠āĻāĻāĻāĻŋ āϤā§āϰāĻŋāĻā§āĻāĻžāĻāĻžāϰ āĻā§āĻŦāĻŋāϞ⧠āĻĻā§āĻāĻž āĻšā§ā§āĻā§āĨ¤ āĻĒā§āϰāϤāĻŋāĻāĻŋ āϏāĻžāϰāĻŋāϤ⧠āĻāĻā§āϰ āϏāĻžāϰāĻŋāϰ āĻā§ā§ā§ āĻāĻāĻāĻŋ āϏāĻāĻā§āϝāĻž āĻŦā§āĻļāĻŋ āϰā§ā§āĻā§āĨ¤ 1 āϏāĻžāϰāĻŋāϤ⧠11 āϏāĻāĻā§āϝāĻž āϰā§ā§āĻā§ āĻāĻŦāĻ āϏāĻžāϰāĻŋāϰ āϏāĻāĻā§āϝāĻžāĻā§āϞā§āϰ āϝā§āĻāĻĢāϞ āĻāϤ?
The consecutive counting numbers are written in a triangular table, as shown, with one more number in each successive row. What is the sum of the numbers in the row that contains 11?
3. āĻĻā§āĻāĻŋ āϏāĻŽā§āĻĒā§āϰā§āĻŖ āĻā§āĻŖā§āϰ āϏāĻŽāώā§āĻāĻŋ āĻĻā§āĻāĻŋ āĻĒā§āϰā§āĻŖ āĻā§āĻŖā§āϰ āϏāĻŽāώā§āĻāĻŋ āĻĨā§āĻā§ āĻāϤ āĻĄāĻŋāĻā§āϰāĻŋ āĻŦā§āĻļāĻŋ?
What is the difference between the sums of two supplementary angles and two complementary angles?
4. āĻāĻāĻāĻŋ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āĻĒā§āϰāϤāĻŋ āϏā§āĻā§āύā§āĻĄā§ āύāĻŋāĻā§āϰ 3 āĻāĻŋ āĻāĻĒāĻŋ āϤā§āϰāĻŋ āĻāϰā§āĨ¤ āĻāĻāĻžāĻŦā§ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āĻĒā§āϰāϤāĻŋ āϏā§āĻā§āύā§āĻĄā§ āύāĻŋāĻā§āϰ āύāϤā§āύ āĻāĻĒāĻŋ āϤā§āϰāĻŋ āĻāϰāϤ⧠āĻĨāĻžāĻā§āĨ¤ āĻāĻāĻāĻŋ āĻŦāĻžāϰ⧠āĻāĻāĻāĻŋ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āϰā§āĻā§ āĻĻā§āĻā§āĻž āĻšāϞ⧠1 āϏā§āĻā§āύā§āĻĄ āĻĒāϰ⧠āĻŦāĻžāĻā§āϝ⧠āĻŽā§āĻ 4 āĻāĻŋ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āĻšāĻŦā§āĨ¤ 5 āϏā§āĻā§āύā§āĻĄ āĻĒāϰ⧠āĻŦāĻžāĻā§āϝ⧠āĻāϤāĻāĻŋ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āĻĨāĻžāĻāĻŦā§?
A bacterium can make 3 copies of itself every second. If you place a bacterium inside a box, after a second, there will be 4 bacteria in the box. After 5 seconds, how many bacteria will be there in the box?
5. 1010-āĻā§ āĻāϤ āϏāĻāĻā§āϝāĻžāϝāĻŧ āϏā§āĻŦāĻžāĻāĻžāĻŦāĻŋāĻ āϏāĻāĻā§āϝāĻž āĻĻā§āĻŦāĻžāϰāĻž āĻāĻžāĻ āĻāϰāĻž āϝāĻžā§, āϝāĻžāϤ⧠āĻāĻžāĻāĻļā§āώ āĻļā§āύā§āϝ āĻšā§?
How many numbers are there by which 1010 is divisible without any remainders?
6. abc āĻāĻāĻāĻŋ āϤāĻŋāύ āĻ āĻāĻā§āϰ āϏāĻāĻā§āϝāĻž āĻāĻŦāĻ a – c = 2āĨ¤ abc – cba -āĻāϰ āĻŽāĻžāύ āĻāϤ? [c > 0]
abc is a three-digit number and a â c = 2. What is the value of abc â cba? [c > 0]
7. āĻāĻāĻāĻŋ ā§Š āĻŽāĻŋāĻāĻžāϰ āĻŦā§āϝāĻžāϏāĻžāϰā§āϧā§āϰ āĻŦā§āϤā§āϤā§āϰ āĻĒāϰāĻŋāϧāĻŋāĻā§ āϏāϰāϞāϰā§āĻāĻž āĻŦāĻžāύāĻžāύ⧠āĻšāϞā§āĨ¤ āĻĒā§āϰāϤāĻŋāĻŦāĻžāϰ āϏā§āĻ āϰā§āĻāĻž āĻŦāϰāĻžāĻŦāϰ āĻĸā§āĻāĻā§āϞ⧠āĻļā§āϰ⧠āĻāϰāĻ˛ā§ ā§Š āĻŽāĻŋāĻāĻžāϰ āĻĒā§āϰāϤāĻŋ āϏā§āĻā§āύā§āĻĄā§ āϏāĻŽāĻžāύāĻāĻžāĻŦā§ āĻāϞā§āĨ¤ āĻŦā§āϤā§āϤā§āϰ āĻāĻ āĻĒā§āϰāĻžāύā§āϤ āĻĨā§āĻā§ āĻ āύā§āϝ āĻĒā§āϰāĻžāύā§āϤ⧠āϝā§āϤ⧠āϤāĻžāϰ āĻĒā§āϰā§ā§āĻāύā§āϝāĻŧ āϏāĻŽāϝāĻŧ āĻāϤ āϏā§āĻā§āύā§āĻĄ?
The circumference of a circle with a radius of 3 meters is turned into a straight line. Prottoy starts running along the line at a uniform velocity of 3Ī meters per second. How long (in seconds) would it take him to go from one end of the straight line to the other?
8.ABC āĻāĻāĻāĻŋ āϏāĻŽāĻā§āĻŖā§ āϤā§āϰāĻŋāĻā§āĻ, āϝā§āĻāĻžāύ⧠A āĻā§āĻŖāĻāĻŋ āϏāĻŽāĻā§āĻŖāĨ¤ D, BC-āĻāϰ āĻāĻĒāϰ āĻāĻŽāύ āĻāĻāĻāĻŋ āĻŦāĻŋāύā§āĻĻā§ āϝā§āύ DA = DCāĨ¤ D-āĻāϰ āĻŽāĻžāϧā§āϝāĻŽā§ āĻ āĻā§āĻāĻŋāϤ AB āĻāϰ āϏāĻŽāĻžāύā§āϤāϰāĻžāϞ āϰā§āĻāĻžāĻāĻŋ AC-āĻā§ E āĻŦāĻŋāύā§āĻĻā§āϤ⧠āĻā§āĻĻ āĻāϰā§āĨ¤ āϝāĻĻāĻŋ AB = 6 āĻšā§, āϤāĻžāĻšāϞ⧠DE āĻāϰ āĻĻā§āϰā§āĻā§āϝ āĻāϤ?
ABC is a right-angled triangle, where, the angle A is a right-angle. D is a point on BC such that, DA=DC. The line through D parallel to AB intersects AC at E. If AB=6, what is the length of DE?
9. āĻāĻāĻāĻŋ āĻāĻžāĻā§ ā§Ēā§ĻāĻāĻŋ āĻĢāϞ āĻāĻā§, ⧍ā§ĻāĻāĻŋ āĻāĻĒā§āϞ āĻāĻŦāĻ ā§¨ā§ĻāĻāĻŋ āĻ
āύā§āϝ āĻĢāϞāĨ¤ āϝāĻĻāĻŋ āĻŦāύā§āϧ āĻāϰ⧠āϰāĻžāĻāĻž āĻā§ā§āĻŋ āĻĨā§āĻā§ āĻāĻāĻāĻŋ āĻĢāϞ āϤā§āϞāĻž āĻšā§, āύāĻŋāĻāϏāύā§āĻĻā§āĻšā§ āϏā§āĻāĻžāύ āĻĨā§āĻā§ āĻāĻāĻāĻŋ āĻāĻĒā§āϞ āϤā§āϞāĻžāϰ āϏāĻŽā§āĻāĻžāĻŦāύāĻž āĻāϤ?
There are 40 oranges, 20 apples, and 20 lemons in a bag. What is the minimum number of fruits that you have to take out of the bag with your eyes closed before you are sure that one of them is an orange?
10. āĻĸāĻžāĻāĻž āĻĨā§āĻā§ āϏāĻŋāϞā§āĻā§ āĻŦāĻžāϏ/āĻā§āϰā§āύ/āĻĒā§āϰā§āĻŽ āϝāĻžāĻāϝāĻŧāĻž āϝāĻžāϝāĻŧāĨ¤ āϏāĻŋāϞā§āĻ āĻĨā§āĻā§ āϏā§āύāĻžāĻŽāĻāĻā§āĻā§ āĻŦāĻžāϏā§/āĻĒā§āϰā§āĻŽā§ āϝāĻžāĻāϝāĻŧāĻž āϝāĻžāϝāĻŧāĨ¤ āĻĸāĻžāĻāĻž â āϏāĻŋāϞā§āĻ â āϏā§āύāĻžāĻŽāĻāĻā§āĻ â āϏāĻŋāϞā§āĻ â āĻĸāĻžāĻāĻžāĨ¤ āĻāĻ āϝāĻžāϤā§āϰāĻžāϝāĻŧ āĻŽā§āĻ āĻāϰāĻ āĻāϏāĻž-āϝāĻžāĻāϝāĻŧāĻž āĻāϤ āĻšāĻŦā§?
To go to Sylhet from Dhaka, there are three choices of vehicles (bus/train/plane). To go to Sunamganj from Sylhet, there are two choices of vehicles (bus/train). How many ways can you traverse the following route: Dhaka->Sylhet->Sunamganj->Sylhet->Dhaka?
Junior preliminary questions
1. ā§Š āĻĻāĻŋāϝāĻŧā§ āĻŦāĻŋāĻāĻžāĻā§āϝ āĻĒā§āϰāĻĨāĻŽ ā§§ā§Ļā§ĻāĻāĻŋ āϏā§āĻŦāĻžāĻāĻžāĻŦāĻŋāĻ āϏāĻāĻā§āϝāĻžāϰ āϏāĻŽāώā§āĻāĻŋ āĻāϤ?
What is the summation of the first 100 numbers that are divisble by 3 without any remainders?
2. āύāĻŋāĻā§āϰ āϏāĻāĻā§āϝāĻžāĻā§āϞā§āϰ āĻŽāϧā§āϝ⧠āϝā§āĻā§āϞ⧠āĻŽā§āϞāĻŋāĻ āϏāĻāĻā§āϝāĻž, āϤāĻžāĻĻā§āϰ āϏāĻŽāώā§āĻāĻŋ āĻāϤ? āϏāĻāĻā§āϝāĻžāĻā§āϞā§: 2, 3, 6, 7, 9, 10
Find the summation of the prime numbers from the following list: 2, 3, 6, 7, 9, 10
3. ABC āĻāĻāĻāĻŋ āϏāĻŽāĻā§āĻŖā§ āϤā§āϰāĻŋāĻā§āĻ, āϝā§āĻāĻžāύ⧠A āĻā§āĻŖāĻāĻŋ āϏāĻŽāĻā§āĻŖāĨ¤ D,BC-āĻāϰ āĻāĻĒāϰ āĻāĻŽāύ āĻāĻāĻāĻŋ āĻŦāĻŋāύā§āĻĻā§ āϝā§āύ DA = DCāĨ¤ D-āĻāϰ āĻŽāĻžāϧā§āϝāĻŽā§ āĻ āĻā§āĻāĻŋāϤ AB -āĻāϰ āϏāĻŽāĻžāύā§āϤāϰāĻžāϞ āϰā§āĻāĻžāĻāĻŋ AC-āĻā§ E āĻŦāĻŋāύā§āĻĻā§āϤ⧠āĻā§āĻĻ āĻāϰā§āĨ¤ āϝāĻĻāĻŋ AB = 6 āĻšā§, āϤāĻžāĻšāϞ⧠DE āĻāϰ āĻĻā§āϰā§āĻā§āϝ āĻāϤ?
ABC is a right-angled triangle, where, the angle A is a right-angle. D is a point on BC such that, DA=DC. The line through D parallel to AB intersects AC at E. If AB=6, what is the length of DE?
4. abc āĻāĻāĻāĻŋ āϤāĻŋāύ āĻ āĻā§āĻā§āϰ āϏāĻāĻā§āϝāĻž āĻāĻŦāĻ a – c = 21āĨ¤ abc – cba āĻāϰ āĻŽāĻžāύ āĻāϤ? [c > 0]
abc is a three digit number and a â c = 2. What is the value of abc â cba? [c > 0]
5. āĻāĻāĻāĻŋ āĻŦāϏā§āϤā§āϰ āĻāĻĒāϰ āĻĒā§āϰāĻāĻžāĻŦāĻŋāϤ āĻŦāϞ āϞāĻžāϞ, āϏāĻŦā§āĻ, āύā§āϞ, āĻšāϞā§āĻĻ āĻāĻžāϰāĻāĻŋ āĻŦāϞā§āϰ āĻŽāĻžāϧā§āϝāĻŽā§ āĻāĻĒāϏā§āĻĨāĻžāĻĒāĻŋāϤāĨ¤ āϤāĻžāĻĻā§āϰ āϝā§āĻĨ āĻĒā§āϰāĻāĻžāĻŦā§ āĻŦāϏā§āϤā§āĻāĻŋ āĻāϞāϤ⧠āĻļā§āϰ⧠āĻāϰā§āĨ¤ āĻā§āύ āĻŦāϞāĻāĻŋ āĻ āύā§āϝ āĻŦāϞā§āϰ āϝā§āĻĨ āĻĒā§āϰāĻāĻžāĻŦā§āϰ āĻāĻāĻ āĻŦāϞā§āϰ āĻŽāϧā§āϝ⧠āĻ āύā§āϤāϰā§āĻā§āĻā§āϤ āĻĨāĻžāĻāĻŦā§?
In a box, there are red, green, blue, yellow and black marbles. There are 200 marbles of each color. At least how many marbles do you have to pick from the box to guarantee that you have picked 100 marbles of the same color?
6. āĻĸāĻžāĻāĻž āĻĨā§āĻā§ āϏāĻŋāϞā§āĻā§ āĻŦāĻžāϏā§/āĻā§āϰā§āύā§/āĻĒā§āϰā§āĻŽā§ āϝāĻžāĻāϝāĻŧāĻž āϝāĻžāϝāĻŧāĨ¤ āϏāĻŋāϞā§āĻ āĻĨā§āĻā§ āϏā§āύāĻžāĻŽāĻāĻā§āĻā§ āĻŦāĻžāϏā§/āĻā§āϰā§āύ⧠āϝāĻžāĻāϝāĻŧāĻž āϝāĻžāϝāĻŧāĨ¤ āĻĸāĻžāĻāĻž â āϏāĻŋāϞā§āĻ â āϏā§āύāĻžāĻŽāĻāĻā§āĻ â āϏāĻŋāϞā§āĻ â āĻĸāĻžāĻāĻžāĨ¤ āĻāĻ āϝāĻžāϤā§āϰāĻžāϝāĻŧ āĻŽā§āĻ āĻāϰāĻ āĻāϏāĻž-āϝāĻžāĻāϝāĻŧāĻž āĻāϤ āĻšāϤ⧠āĻĒāĻžāϰā§?
To go to Sylhet from Dhaka, there are three choices of vehicles (bus/train/plane). To go to Sunamganj from Sylhet, there are two choices of vehiches (bus/train). How many ways can you traverse the following route: Dhaka->Sylhet->Sunamganj->Sylhet->Dhaka?
7. āĻāĻāĻāĻŋ āϏāĻŽāϤāϞ⧠ā§ŦāĻāĻŋ āĻŦāĻŋāύā§āĻĻā§ āϏāϰāϞāϰā§āĻāĻžāϝāĻŧ āĻ āĻŦāϏā§āĻĨāĻŋāϤ āύāĻž āĻšāϞ⧠āϤāĻžāĻĻā§āϰ āϝā§āĻāϏāĻāĻā§āϝāĻž āĻāϤ āĻšāϤ⧠āĻĒāĻžāϰā§? āϏāĻŦāĻā§āϝāĻŧā§ āĻŦāĻĄāĻŧ āϤā§āϰāĻŋāĻā§āĻ āĻāĻžāĻā§ āĻŦāĻŋāĻāĻā§āϤ āĻāϰāĻž āϏāĻŽā§āĻāĻŦ?
In a plane, 6 distinct lines intersect the interior of a square forming regions within the square. What is the maximum number of regions that can be formed?
8. 51b2cd āĻāĻāĻāĻŋ āĻāϝāĻŧ āĻ āĻā§āĻā§āϰ āĻĒā§āϰā§āĻŖāϏāĻāĻā§āϝāĻž āϝāĻžÂ 5 āĻāĻŦāĻ 11 āĻĻā§āĻŦāĻžāϰāĻž āĻŦāĻŋāĻāĻžāĻā§āϝāĨ¤ āϏāĻāĻā§āϝāĻžāĻāĻŋāϰ āϏāĻŽā§āĻāĻžāĻŦā§āϝ āĻŽāĻžāύā§āϰ āϝā§āĻāĻĢāϞ āĻāϤ?
51b2cd is a six-digit perfect square that is divisible by both 5 and 11. What is the sum of all possible values of it?
9. āϤā§āϰāĻŋāĻā§āĻāĻžāĻāĻžāϰ ABCD-āĻāϰ AB āĻāĻŦāĻ CD āĻĒāϰāϏā§āĻĒāϰ āϏāĻŽāĻžāύā§āϤāϰāĻžāϞ āϰā§āĻāĻžāĨ¤ P, Q āϝāĻĨāĻžāĻā§āϰāĻŽā§ AC āĻāĻŦāĻ BD āϰā§āĻāĻžāϰ āĻŽāϧā§āϝāĻŦāĻŋāύā§āĻĻā§āĨ¤ āϝāĻĻāĻŋ CD = 2020 āĻāĻŦāĻ AB = 1010, āϤāĻŦā§ PQ-āĻāϰ āĻĻā§āϰā§āĻā§āϝ āĻāϤ? 
Let AB and CD be the parallel sides of trapezium ABCD.Let P and Q be the midpoint of the diagonals AC and BD.If CD=2020 and AB=1010 then what is the length of PQ?
10. āĻāĻŋāϤā§āϰ⧠āϝā§āϏāĻŦ āĻŦā§āϤā§āϤ āĻĻā§āĻāĻž āϝāĻžāĻā§āĻā§, āϤāĻžāĻĻā§āϰ āĻŽāϧā§āϝ⧠āĻā§āώā§āĻĻā§āϰāϤāĻŽ āĻŦā§āϤā§āϤā§āϰ āĻŦā§āϝāĻžāϏāĻžāϰā§āϧ 1 āĻāĻāĻāĨ¤ āĻāϰ āĻĒāϰ⧠āĻĒā§āϰāϤāĻŋāĻāĻŋ āĻŦā§āϤā§āϤā§āϰ āĻŦā§āϝāĻžāϏāĻžāϰā§āϧ āĻĒāϰā§āϝāĻžāϝāĻŧāĻā§āϰāĻŽā§ 1 āĻāĻāĻ āĻāϰ⧠āĻŦā§āĻĻā§āϧāĻŋ āĻĒā§āϝāĻŧā§āĻā§āĨ¤ āϏāĻžāĻĻāĻž āĻāĻŦāĻ āĻāĻžāϞ⧠āĻ
āĻāĻļā§āϰ āĻā§āώā§āϤā§āϰāĻĢāϞā§āϰ āĻĒāĻžāϰā§āĻĨāĻā§āϝ āϝāĻĻāĻŋ
āĻŦāϰā§āĻ āĻāĻāĻ āĻšāϝāĻŧ, āϤāĻŦā§ x-āĻāϰ āĻŽāĻžāύ āĻāϤ?
The smallest circle in the following figure has a radius of 1 unit. The circles larger than it has a successive increase of 1 unit in their radii. If the difference of the white and black colored area is
, what is the value of x?