Asia Pacific Mathematical Olympiad for Primary Schools 2004

1. ABCD is a quadrilateral (4 sided figure).
AE and GC are perpendicular to BD. Given that BE = EF = FD, GF = FC and that the total area of ΔABE and ΔDFG is 12.9 cm2, find the area of the quadrilateral ABCD.



2. Teams X and Y work separately on two different projects.
On sunny days, team X can complete the work in 12 days while team Y needs 15 days.
On rainy days, team X’s efficiency decreases by 50% while team Y’s efficiency decreases by 25%.
Given that the two teams started and ended the projects at the same time, how many rainy days are there?

3. 2004 students arrange themselves in a row. In the first round of counting, they number themselves
1, 2, 3, 1, 2, 3, 1, 2, 3 … from left to right.
In the second round of counting, they number themselves
1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5,… from right to left.
Find the number of students whose sum of numbers in the first and second rounds of counting is 5.

4. Mrs Tan and Mrs Wong met each other at a park.
Mrs Tan       :         “Hi, how are you? How are your children?
You have three if I remember correctly.
But how old are they now?”
Mrs Wong    :         “Yes, I have three children.
The product of their ages is equal to 36.
The sum of their ages is equal to the number of chairs over there.”
Mrs Tan counted the number of chairs, thought for a while and said
“ I still can’t figure out the ages of your children.”

What are the possible ages of the three children?
(Assume whole number for ages.)

5.     Tom walks up a staircase.
Each time he can either take one step or two steps.
How many ways are there for Tom to walk up a ten-step staircase?

6. Two points A and B are 1100 m apart.
Alice and Ben leave point A at the same time and travel to and fro along a straight road between A and B at uniform speeds. Alice and Ben travel at 60 m/min and 160 m/min respectively. They both stop after 40 minutes.
(i) At which meeting are they nearest to point B?
(ii) Find this nearest distance in metre.
»»  READMORE...

Mathematics Olympiad : 2005 Pennsylvania State University Hazleton

Mathematics Olympiad
Pennsylvania State University Hazleton
Fall 2005
First Round


Problem 1
A train was moving in the same direction for 5 ½ hours. It is known that the train covered exactly 100 km over any 1hour time interval. Is it true that the train was moving at a constant speed? Is it true that its average speed was 100 km/h?

Problem 2
Solve the equation : 2 . (sin x + cos x) = tan2005 x + cot2005 x .

Problem 3
Let a1 =  32005 , and let an+1 be the sum of digits of an , n 1. Find a 5 .

Problem 4
Show that there exists such a positive integer N that the fractional part of N . 2005 is less than 20052005 .

Problem 5
Let f (x) be continuous on the interval [0, 2005] such that f (0) = f (2005) . Show that the graph of f (x) has a chord of length 1 parallel to the x axis.

Problem 6
The vertices of a triangle lie on a circle of radius 2005. Is it possible to put this triangle inside a circle of radius 2004?
»»  READMORE...

Dividing fractions word problems

Example #1:

An Italian sausage is 8 inches long. How many pieces of sausage can be cut from the 8-inch piece of sausage if each piece is to be two-thirds of an inch ?

Solution

Since you are trying to find out how many two-thirds there are in 8, it is a division of fractions problem.

So, divide 8 by 2/3

8 ÷ 2/3 = 8/1 ÷ 2/3 = 8/1 × 3/2 = 24/2 = 12

Therefore, you can make 12 pieces having a length of 2/3 inches


Example #2

How many halves are there in six-fourth?

Again, since you are trying to find out how many halves there are in six-fourth, it is a division of fractions problem.

So, divide 6/4 by 1/2

6/4 ÷ 1/2 = 6/4 × 2/1 = 12/4 = 3

Therefore, there are 3 halves in six-fourth


Example #3:
An airplane covers 50 miles in 1/5 hours. How many miles can the airplane cover in 5 hours?

This problem is a combination of division and multiplication of fractions

First, find out how many fifths (1/5) are there in 5. This is a division of fractions problem

So, divide 5 by 1/5

5 ÷ 1/5 = 5/1 ÷ 1/5 = 5/1 × 5/1 = 25/1 = 25

Then, multiply 50 by 25 to get 1250

In 5 hours, the airplane will cover 1250 miles
»»  READMORE...

DIVISIBILITY

Divisible by 2
Numbers are divisible by 2 if the ones digit is evenly divisible by 2. This means that even numbers are divisible by 2.

Divisible by 3
Numbers are divisible by 3 if the sum of all the individual digits is evenly divisible by 3. For example, the sum of the digits for the number 3627 is 18, which is evenly divisible by 3 so the number 3627 is evenly divisible by 3.

Divisible by 4
Whole numbers are divisible by 4 if the number formed by the last two individual digits is evenly divisible by 4. For example, the number formed by the last two digits of the number 3628 is 28, which is evenly divisible by 4 so the number 3628 is evenly divisible by 4.

Divisible by 5
Numbers are evenly divisible by 5 if the last digit of the number is 0 or 5.

Divisible by 6
Numbers are evenly divisible by 6 if they are evenly divisible by both 2 AND 3. Even numbers are always evenly divisible by 2. Numbers are evenly divisible by 3 if the sum of all the individual digits is evenly divisible by 3. For example, the sum of the digits for the number 3627 is 18, which is evenly divisible by 3 but 3627 is an odd number so the number 3627 is not evenly divisible by 6.

Divisible by 7
To determine if a number is divisible by 7, take the last digit off the number, double it and subtract the doubled number from the remaining number. If the result is evenly divisible by 7 (e.g. 14, 7, 0, -7, etc.), then the number is divisible by seven. This may need to be repeated several times.

Example: Is 3101 evenly divisible by 7?

 310   - take off the last digit of the number which was 1
   -2   - double the removed digit and subtract it
 308   - repeat the process by taking off the 8
  -16    - and doubling it to get 16 which is subtracted
   14    - the result is 14 which is a multiple of 7  

Divisible by 8
Numbers are divisible by 8 if the number formed by the last three individual digits is evenly divisible by 8. For example, the last three digits of the number 3624 is 624, which is evenly divisible by 8 so 3624 is evenly divisible by 8.

Divisible by 9 and 10
A number is divisible by 10 only if the last digit is a 0. Numbers are divisible by 9 if the sum of all the individual digits is evenly divisible by 9. For example, the last sum of the digits of the number 3627 is 18, which is evenly divisible by 9 so 3627 is evenly divisible by 9.
»»  READMORE...

powered by Blogger | WordPress by Newwpthemes | Converted by BloggerTheme