Mock Aiome
Mock Aiome
Mock Aiome
trumpeter
14 September 2015
Submit all submissions to the Google Form here. As usual, all answers are three digit
integers from 000-999, inclusive. As Google Forms apparently doesnt know the difference
between 001 and 1, it doesnt matter if you type 001 or 1 in. Always good practice to
type out 001 to remember format for the actual AIME, though.
Problem Writer: trumpeter
Problem Selection Committee: anduril, MathStudent2002, qwerty137, suli, trumpeter
Problem Editors: anduril, MathStudent2002, qwerty137, suli, trumpeter
j=1
k=1
is not an integer?
7. Let ABC be a triangle and D the midpoint of BC. Let X and Y be the circumcenters of 4ABD and 4ACD, respectively. Furthermore, let E be the midpoint
of XY . Given that AB = 39, BC = 56, and AC = 25, the length of AE can be
for relatively prime positive integers m and n. Compute m + n.
expressed as m
n
8. Define the inverse of a modulo n as the integer b such that ab 1 is divisible by
n. If there is no such integer b, the inverse does not exist. Now, define f (x) as a
function that outputs 1 if x has an inverse modulo 2015 and 1 if x does not have
an inverse modulo 2015. Compute the remainder when
2015
X
f (n) n
n=1
is divided by 1000.
9. A, B, C, and D are points in a plane such that B, C, and D are collinear and
BAD + DAC = BAC = 126 . Given that AD = 1, the minimum possible
value of
BA
CA
+
sin BAD sin CAD
10. Let P (x) = x3 2x + 3 and Q(x) = x7 6x5 + 9x4 + 12x3 36x2 + 17x + 36. Let
z be a randomly selected root of P (x). Compute the expected value of Q(z).
11. Let n be the smallest positive integer such that the last 2015 digits of 21n are
000 . . . 0001, where there are 2014 0s followed by one 1. Compute the remainder
when the number of positive factors of n is divided by 1000.
12. Let d (x) be the number of distinct digits in the decimal representation of x and
e (n), for positive integers n, be the expected value of d (x) for x = 1, 2, 3, . . . , 10n .
Then,
a bn c
e (n) = 10
d 10n
for positive integers a, b, c, and d such that GCD (a, c, d) = 1. Compute a+b+c+d.
13. Let x and n be integers such that n is positive and
x2 = (10n + 12) x + 4n3 + 4n2 + 6n + 9 .
In addition, x is the larger solution to the quadratic in x above. Compute the
smallest possible value of x 2n.
14. Let ABCD be a scalene quadrilateral that has both a circumcircle and incircle. If
AC BD = 280 and AB, BC, CD, and AD are integers, compute the minimum
possible perimeter of quadrilateral ABCD. Note: a scalene quadrilateral is one
that has no two sides that are equal.
15. We can show that
X
i
i1
1
cb
=
ln
ae
,
2i i + 1 i + 2
i=1
where a, b, and c are positive integers such that GCD (b, c) = 1. Compute the
remainder when a + b + c is divided by 1000.