
3. (a) Jimmy is baking two large identical triangular
cookies, 4ABC and 4DEF . Each cookie is in
the shape of an isosceles right-angled triangle. The
length of the shorter sides of each of these triangles
is 20 cm. He puts the cookies on a rectangular
baking tray so that A, B, D, and E are at the
vertices of the rectangle, as shown. If the distance
between parallel sides AC and DF is 4 cm, what is
the width BD of the tray?
(b) Determine all values of x for which
x
2
+ x + 4
2x + 1
=
4
x
.
4. (a) Determine the number of positive divisors of 900, including 1 and 900, that are
perfect squares. (A positive divisor of 900 is a positive integer that divides exactly
into 900.)
(b) Points A(k, 3), B(3, 1) and C(6, k) form an isosceles triangle. If ∠ABC = ∠ACB,
determine all possible values of k.
5. (a) A chemist has three bottles, each containing a mixture of acid and water:
• bottle A contains 40 g of which 10% is acid,
• bottle B contains 50 g of which 20% is acid, and
• bottle C contains 50 g of which 30% is acid.
She uses some of the mixture from each of the bottles to create a mixture with
mass 60 g of which 25% is acid. Then she mixes the remaining contents of the
bottles to create a new mixture. What percentage of the new mixture is acid?
(b) Suppose that x and y are real numbers with 3x + 4y = 10. Determine the
minimum possible value of x
2
+ 16y
2
.
6. (a) A bag contains 40 balls, each of which is black or gold. Feridun reaches into the
bag and randomly removes two balls. Each ball in the bag is equally likely to be
removed. If the probability that two gold balls are removed is
5
12
, how many of
the 40 balls are gold?
(b) The geometric sequence with n terms t
1
, t
2
, . . . , t
n−1
, t
n
has t
1
t
n
= 3. Also, the
product of all n terms equals 59 049 (that is, t
1
t
2
···t
n−1
t
n
= 59 049). Determine
the value of n.
(A geometric sequence is a sequence in which each term after the first is obtained
from the previous term by multiplying it by a constant. For example, 3, 6, 12 is
a geometric sequence with three terms.)