European Girls' Mathematical Olympiad

Description: The European Girls' Mathematical Olympiad (EGMO) is a mathematics competition for high school girls from European countries. It is held annually and is one of the most prestigious mathematics competitions in the world.
Number of Questions: 15
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In a triangle ABC, the angle bisector of angle A intersects the side BC at point D. If AB = 10 cm, AC = 12 cm, and AD = 8 cm, find the length of BD.

  1. 4 cm

  2. 6 cm

  3. 8 cm

  4. 10 cm


Correct Option: B
Explanation:

Using the Angle Bisector Theorem, we have BD/DC = AB/AC. Substituting the given values, we get BD/DC = 10/12. Solving for BD, we get BD = 10/12 * DC. Since DC = BC - BD, we have BD = 10/12 * (12 - BD). Solving for BD, we get BD = 6 cm.

A circle has a radius of 10 cm. What is the area of the sector of the circle formed by a central angle of 60 degrees?

  1. 25π cm^2

  2. 50π cm^2

  3. 75π cm^2

  4. 100π cm^2


Correct Option: A
Explanation:

The area of a sector of a circle is given by the formula A = (θ/360) * πr^2, where θ is the central angle in degrees and r is the radius of the circle. Substituting the given values, we get A = (60/360) * π(10)^2 = 25π cm^2.

A train leaves a station at 10:00 AM and travels at a speed of 60 mph. Another train leaves the same station at 11:00 AM and travels in the same direction at a speed of 75 mph. At what time will the second train overtake the first train?

  1. 12:00 PM

  2. 12:30 PM

  3. 1:00 PM

  4. 1:30 PM


Correct Option: B
Explanation:

Let t be the time in hours after 11:00 AM when the second train overtakes the first train. The distance traveled by the first train in t hours is 60t miles, and the distance traveled by the second train in t hours is 75t miles. Since the second train overtakes the first train, we have 75t = 60t + 60. Solving for t, we get t = 2.5 hours. Therefore, the second train will overtake the first train at 11:00 AM + 2.5 hours = 1:30 PM.

A company has 100 employees, of which 60% are women and 40% are men. If 20% of the women and 30% of the men are promoted, how many employees in total are promoted?

  1. 22

  2. 24

  3. 26

  4. 28


Correct Option: C
Explanation:

The number of women in the company is 60% of 100, which is 60. The number of men in the company is 40% of 100, which is 40. The number of women promoted is 20% of 60, which is 12. The number of men promoted is 30% of 40, which is 12. Therefore, the total number of employees promoted is 12 + 12 = 24.

A bag contains 10 red balls, 15 blue balls, and 20 green balls. If a ball is randomly selected from the bag, what is the probability that it is not a red ball?

  1. 1/2

  2. 2/5

  3. 3/5

  4. 4/5


Correct Option: C
Explanation:

The total number of balls in the bag is 10 + 15 + 20 = 45. The number of balls that are not red is 45 - 10 = 35. Therefore, the probability of selecting a ball that is not red is 35/45 = 3/5.

In a right triangle ABC, the angle B is 30 degrees and the hypotenuse AC is 10 cm. Find the length of the side AB.

  1. 5 cm

  2. 5√3 cm

  3. 10 cm

  4. 10√3 cm


Correct Option: B
Explanation:

In a right triangle, the sine of an angle is equal to the ratio of the opposite side to the hypotenuse. In this case, sin(B) = AB/AC. Substituting the given values, we get sin(30) = AB/10. Solving for AB, we get AB = 10 * sin(30) = 5√3 cm.

A farmer has 100 acres of land. He plants corn on 40% of the land, soybeans on 30% of the land, and wheat on the rest of the land. How many acres of land does he plant wheat on?

  1. 20

  2. 30

  3. 40

  4. 50


Correct Option: B
Explanation:

The farmer plants corn on 40% of the land, which is 40% of 100 acres = 40 acres. He plants soybeans on 30% of the land, which is 30% of 100 acres = 30 acres. Therefore, he plants wheat on 100 acres - 40 acres - 30 acres = 30 acres.

A company has 500 employees, of which 60% are women and 40% are men. If 20% of the women and 30% of the men are promoted, how many women are promoted?

  1. 60

  2. 72

  3. 84

  4. 96


Correct Option: B
Explanation:

The number of women in the company is 60% of 500, which is 300. The number of men in the company is 40% of 500, which is 200. The number of women promoted is 20% of 300, which is 60. The number of men promoted is 30% of 200, which is 60. Therefore, the total number of women promoted is 60.

A train leaves a station at 10:00 AM and travels at a speed of 70 mph. Another train leaves the same station at 11:00 AM and travels in the same direction at a speed of 80 mph. At what time will the second train overtake the first train?

  1. 12:00 PM

  2. 12:30 PM

  3. 1:00 PM

  4. 1:30 PM


Correct Option: B
Explanation:

Let t be the time in hours after 11:00 AM when the second train overtakes the first train. The distance traveled by the first train in t hours is 70t miles, and the distance traveled by the second train in t hours is 80t miles. Since the second train overtakes the first train, we have 80t = 70t + 70. Solving for t, we get t = 70 hours. Therefore, the second train will overtake the first train at 11:00 AM + 70 hours = 1:30 PM.

A company has 200 employees, of which 40% are women and 60% are men. If 25% of the women and 35% of the men are promoted, how many employees in total are promoted?

  1. 30

  2. 35

  3. 40

  4. 45


Correct Option: B
Explanation:

The number of women in the company is 40% of 200, which is 80. The number of men in the company is 60% of 200, which is 120. The number of women promoted is 25% of 80, which is 20. The number of men promoted is 35% of 120, which is 42. Therefore, the total number of employees promoted is 20 + 42 = 62.

A bag contains 15 red balls, 20 blue balls, and 25 green balls. If a ball is randomly selected from the bag, what is the probability that it is a blue ball?

  1. 1/2

  2. 2/5

  3. 3/5

  4. 4/5


Correct Option: B
Explanation:

The total number of balls in the bag is 15 + 20 + 25 = 60. The number of blue balls in the bag is 20. Therefore, the probability of selecting a blue ball is 20/60 = 2/5.

In a right triangle ABC, the angle C is 45 degrees and the hypotenuse AC is 12 cm. Find the length of the side AB.

  1. 6 cm

  2. 6√2 cm

  3. 8 cm

  4. 8√2 cm


Correct Option: B
Explanation:

In a right triangle, the cosine of an angle is equal to the ratio of the adjacent side to the hypotenuse. In this case, cos(C) = AB/AC. Substituting the given values, we get cos(45) = AB/12. Solving for AB, we get AB = 12 * cos(45) = 6√2 cm.

A farmer has 120 acres of land. He plants corn on 50% of the land, soybeans on 30% of the land, and wheat on the rest of the land. How many acres of land does he plant wheat on?

  1. 24

  2. 36

  3. 48

  4. 60


Correct Option: B
Explanation:

The farmer plants corn on 50% of the land, which is 50% of 120 acres = 60 acres. He plants soybeans on 30% of the land, which is 30% of 120 acres = 36 acres. Therefore, he plants wheat on 120 acres - 60 acres - 36 acres = 24 acres.

A company has 600 employees, of which 40% are women and 60% are men. If 20% of the women and 30% of the men are promoted, how many women are promoted?

  1. 96

  2. 108

  3. 120

  4. 132


Correct Option: A
Explanation:

The number of women in the company is 40% of 600, which is 240. The number of men in the company is 60% of 600, which is 360. The number of women promoted is 20% of 240, which is 48. The number of men promoted is 30% of 360, which is 108. Therefore, the total number of women promoted is 48.

A train leaves a station at 10:00 AM and travels at a speed of 80 mph. Another train leaves the same station at 11:00 AM and travels in the same direction at a speed of 90 mph. At what time will the second train overtake the first train?

  1. 12:00 PM

  2. 12:30 PM

  3. 1:00 PM

  4. 1:30 PM


Correct Option: B
Explanation:

Let t be the time in hours after 11:00 AM when the second train overtakes the first train. The distance traveled by the first train in t hours is 80t miles, and the distance traveled by the second train in t hours is 90t miles. Since the second train overtakes the first train, we have 90t = 80t + 80. Solving for t, we get t = 80 hours. Therefore, the second train will overtake the first train at 11:00 AM + 80 hours = 1:30 PM.

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