Math Contest : Nassau County Interscholastic Mathematics League (3)


5. Chauncey goes up a flight of 8 stairs. With each step, he goes up either one or two stairs. Find the number of different sequences of steps he can take to the top.
Note that leaping one stair and then two stairs is different from leaping two stairs and then one stair.

6. In convex quadrilateral ABCD, diagonal AC is perpendicular to diagonal BD, AB = 10, BC = 5, and CD = 11. Find AD.
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Math Contest : Nassau County Interscholastic Mathematics League


3. Find the sum of the coefficients in the expansion of (3x – 1)4

4. Point A is on a circle whose center is O, AB is tangent to the circle, AB = 6, D is inside the circle, OD = 2, DB intersects the circle at C, and BC = DC = 3. If r is the length of the radius of the circle, find r2.
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Nassau County Interscholastic Mathematics League : Contest 1 - 2010/2011


1. Compute 19.272 + 11.732 + (38.54)(11.73).

2. Point A is outside a circle and AB and AC are tangent to the circle at B and C, respectively. Points P and R are on AB and BC, respectively, PR is tangent to the circle at Q, and AB = 20. Find the perimeter of triangle APR.
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ABACUS - JANUARY 2012 : LEVEL 7 - 8


PROBLEM 1. The ages of a father and his two different-aged sons are the powers of the same prime number. Last year everybody's age was a prime number. How old are they now?

PROBLEM 2. Could the sum of seven consecutive integers be a prime number?

PROBLEM 3. A 5-digit number is divisible by 7, 8, and 9. The number created from the first two digits is a prime number, 1 greater than a square number, and the sum of these two digits is a two-digit number. Find this 5-digit number.

PROBLEM 4. Every digit of a 5-digit number is either 1 or a prime number. Not only that, but any number created by any 2, 3, or 4 consecutive digits of this number are prime numbers also. Find this number, and check if it is a prime number or not.

PROBLEM 5. Can you put the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 into two groups so that the sums of the numbers in each group is the same? Can you do this to get the same product in each group?

PROBLEM 6. Are there any five consecutive whole numbers, which can be put into two groups so that the product of the numbers in each group is the same?

PROBLEM 7. In some cases, when 22022 and 20222 are divided by the same 3-digit number, they give the same remainder. Which one of these divisors can be determined by the remainder?

PROBLEM 8. Find a, b, c, and d, such that abb = bccbdc
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NUMBER CARDS

Take 10 number cards with the following numbers on them (one number on each card): 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Make a pile of them by putting one on top of another, and hold the pile in your hands. Now put the top card on the table, put the next top card on the bottom of the pile in your hands, put the next top card on the table, the next top card on the bottom of the pile, and so on, until you run out of cards. In what order do you have to stack the cards at the beginning if you want the cards to be on the table at the end in the following order : 1, 2, 3, 4, 5, 6, 7, 8, 9, 10?
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HONEST AND LIAR

Two kinds of people live on an island: honest and liar. Honest people always say the truth, liars always lie. One day we asked everybody in a group of 5 people from this island who know each other: "How many of you are honest?" We received the following answers: 0, 1, 2, 3, 4.
How many of them are honest?
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TEAM POINTS

In a league the teams received a total of 420 points. You got 2 points for a victory, 1 point for a tie, and 0 points for a loss. How many teams were there in the league if every team played every team twice?
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