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senior Division Competition paper
instruCtions anD information
GeneraL
1. Do not open the booklet until told to do so by your teacher.
2. NO calculators, slide rules, log tables, maths stencils, mobile phones or other calculating aids are
permitted. Scribbling paper, graph paper, ruler and compasses are permitted, but are not essential.
3. Diagrams are NOT drawn to scale. They are intended only as aids.
4. There are 25 multiple-choice questions, each with 5 possible answers given and 5 questions that
require a whole number answer between 0 and 999. The questions generally get harder as you
work through the paper. There is no penalty for an incorrect response.
5. This is a competition not a test; do not expect to answer all questions. You are only competing
against your own year in your own State or Region so different years doing the same paper
are not compared.
6. Read the instructions on the answer sheet carefully. Ensure your name, school name and school
year are entered. It is your responsibility to correctly code your answer sheet.
7. When your teacher gives the signal, begin working on the problems.
tHe ansWer sHeet
1. Use only lead pencil.
2. Record your answers on the reverse of the answer sheet (not on the question paper) by FULLY
colouring the circle matching your answer.
3. Your answer sheet will be scanned. The optical scanner will attempt to read all markings even
if they are in the wrong places, so please be careful not to doodle or write anything extra on
the answer sheet. If you want to change an answer or remove any marks, use a plastic eraser
and be sure to remove all marks and smudges.
inteGritY of tHe Competition
The AMT reserves the right to re-examine students before deciding whether to grant official status
to their score.
a u s t r a l i a n s c h o o l Y e a r s 1 1 a n d 1 2
t i m e a l l o w e d : 7 5 m i n u t e s
©AMT P
ublishing2012
AMTTliMiTedAcn083 950 341
A
u s t r A l i A n
M
At h e M At i c s
c
o M p e t i t i o n
A n
A c T i v i T y
o f
T h e
A u s T r A l i A n
M A T h e M A T i c s
T r u s T
t h u r s daY 2 au g u s t 2 01 2
Senior Division
Questions 1 to 10, 3 marks each
1.
The expression 2012
− 2.012 equals
(A) 2010.012
(B) 2010.998
(C) 2009.998
(D) 2012.012
(E) 2009.988
2.
By what number must 6 be divided by to obtain
1
3
as a result?
(A) 18
(B)
1
2
(C)
1
18
(D) 2
(E) 9
3.
In the diagram, the size in degrees of three
angles are given. Find the value of x.
(A) 90
(B) 95
(C) 100
(D) 110
(E) 120
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...... ...... ...... ...... ...... ...... ...... ............ ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ....30
◦
50
◦
40
◦
x
◦
4.
The straight line joining the points (0,2) and (2,8) also passes through
(A) (4,14)
(B) (3,14)
(C) (3,10)
(D) (4,10)
(E) (2,0)
5.
What is the number that is halfway between
a
b
and
c
b
?
(A) 1
(B)
a
− c
b
(C)
a + c
b
(D)
a
− c
2b
(E)
a + c
2b
6.
If 3
16
× 27
10
= 9
x
, then x equals
(A) 18
(B) 21
(C) 23
(D) 26
(E) 27
7.
If
p
p
− 2q
= 3 then
p
q
equals
(A) 3
(B)
1
3
(C)
2
3
(D) 2
(E)
−3
S 2
8.
Two perfume bottles are similar in shape but one has twice the height of the other.
Together they contain 270 mL of perfume. How much perfume, in millilitres, is in
the smaller bottle?
(A) 27
(B) 30
(C) 50
(D) 54
(E) 90
9.
If x and y are positive integers, how many integers are greater than xy but less
than x(y + 1)?
(A) 1
(B) x
− 2
(C) y
− 1
(D) x
(E) x
− 1
10.
The architecture of Federation Square in Melbourne is based on frames as shown
in which a large triangle is subdivided into 5 identical triangles, each similar to the
large triangle.
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...If the shortest side of one of the smallest triangles is 1 m, how many metres of
framing are required to construct the whole shape?
(A) 20
(B) 8 + 4
√
5
(C) 10 + 4
√
5
(D) 12 + 4
√
5
(E) 15 + 5
√
5
Questions 11 to 20, 4 marks each
11.
Five distinct integers are arranged in order, with the smallest being 5 and the
largest being 16. The mean of the five integers is prime and is also equal to the
median. The number of possibilities for the second largest number is
(A) 0
(B) 1
(C) 2
(D) 3
(E) 4
12.
The average of 3
3
2
, 3
5
2
and 3
7
2
is
(A) 9
√
3
(B) 10
√
3
(C) 11
√
3
(D) 12
√
3
(E) 13
√
3
S 3
13.
Triangle P QR is right-angled at R. The circle with centre P and radius P R cuts
P Q at S and the circle with centre Q and radius QS cuts QR at T .
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... ... ... ... .. ... ... ... .. ... ...
P
R
T
Q
S
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ... ... ... ... ... .... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ....If T bisects QR, then the ratio QS : SP equals
(A) 7 : 12
(B) 5 : 12
(C) 5 : 8
(D) 3 : 4
(E) 2 : 3
14.
In a three-game series of basketball with just two teams, Wollongong and Townsville,
the probability that Wollongong will win each game is twice the probability that
Townsville will win. What is the probability that Townsville will win the series?
(A)
1
3
(B)
2
9
(C)
5
27
(D)
7
27
(E)
5
18
15.
The square shown has side 20 cm. A ‘V’ is shaded as shown.
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... ... ... ... ... ... ... .. ...... ...... ...... ...... ...... ...... ...... ... ... ... ... ... ... ... ... ... ... ...... ...... ...... ...... ...... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .... .... .... .... .... ....... .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. . .. .. .. .. .. . .. .. .. .. .. . .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. . .. .. .. .. . .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ...
4
12
4
8
4
8
The area shaded, in square centimetres, is
(A) 136
(B) 150
(C) 164
(D) 188
(E) 200
16.
If the number 10
2012
− 2012 is written out in full, the sum of its digits is
S 4
17.
The side lengths of a right-angled triangle are in geometric progression and the
shortest side has length 2. What is the length of the hypotenuse?
(A) 1 +
√
5
(B)
√
10
(C) 3
√
2
− 1
(D)
√
11
(E) 2
√
3
18.
Jess marks four of eight identical cards with an X and the other four with a Y .
She shuffles them and puts them face down in a row and challenges Mike to guess
the letter on each card. Mike decides to choose XY XY XY XY . What is the
probability of Mike correctly guessing all eight cards?
(A)
4
8
(B)
1
70
(C)
1
85
(D)
1
90
(E)
1
256
19.
The diagonal of a rectangular tile with integer sides is one-third of the length of
the diagonal of a row of tiles identical to the original one. If the perimeter of the
single tile is 24 cm, how many tiles are in the row?
(A) 3
(B) 6
(C) 9
(D) 12
(E) 15
20.
In the
4P QR,
6
R = 2
6
P , P R = 5 and QR = 4. The length of P Q is
(A) 2
√
10
(B) 6
(C) 7
(D) 2
√
7
(E) 5
√
2
Questions 21 to 25, 5 marks each
21.
Let p(x) be a polynomial such that
p(x) = (x
− 2)
2012
(x + 2012) + (x
− 2)
2011
(x + 2011) +
· · · + (x − 2)(x + 1).
The sum of the coefficients of p(x) is
(A) 1006
(B) 2012
(C) 2027090
(D) 0
(E) 1
22.
Twelve points are marked on the circumference of a circle. All possible straight
lines that join any two of these points are drawn. We will call a pair of such lines
free if the two lines in the pair do not intersect and have no common endpoints.
The total number of free pairs is
S 5
23.
If x and y are positive integers which satisfy x
2
− 8x − 1001y
2
= 0, what is the
smallest possible value of x + y?
(A) 73
(B) 100
(C) 102
(D) 114
(E) 136
24.
A spherical ball of radius 1 rests inside a holder in the shape of an inverted pyramid.
The pyramid has a horizontal square top and its other faces are equilateral triangles.
It is large enough to enclose the ball.
... ... ... ... ... ... ... ... ... ... .... .... .... .... .... .... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .... .... .... ... ... ... ... ... ... ... ...... ...... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...... ...... ... ...... ...... ...... ...... ...... ...
X
How far is the centre of the ball above the apex X of the pyramid?
(A)
√
2
(B)
3
2
(C) 3
−
√
2
(D)
√
3
(E) 2
25.
In ‘base
−2’ notation, digits are 0 and 1 only and the places go up in powers of
−2. For example, 110110 stands for
1
× (−2)
5
+ 1
× (−2)
4
+ 0
× (−2)
3
+ 1
× (−2)
2
+ 1
× (−2) + 0 × 1 = −14.
If the decimal number 2000 is written in base
−2 notation, how many non-zero
digits does it contain?
(A) 3
(B) 4
(C) 5
(D) 6
(E) 7
For questions 26 to 30, shade the answer as an integer from 0 to 999 in
the space provided on the answer sheet.
Question 26 is 6 marks, question 27 is 7 marks, question 28 is 8 marks,
question 29 is 9 marks and question 30 is 10 marks.
26.
A courier company has motorbikes that can travel 300 km on a full tank of fuel.
Two couriers, Anna and Brian, set off from the depot together to deliver a letter to
Connor’s house. They can transfer fuel between the bikes at any time but do not
return to the depot to get more fuel. While only one bike is required to deliver the
letter, both must return to the depot. What is the greatest distance, in kilometres,
that Connor’s house could be from the depot?
S 6
27.
Twenty-eight points are equally spaced around the circumference of a circle. What
is the total number of triangles whose three vertices are from those twenty-eight
points and the size of one of the angles is twice the size of another?
28.
In the grid shown, we need to fill in the squares with numbers so that the number
in every square, except for the corner ones, is the average of its neighbours. The
edge squares have three neighbours, the others four.
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
