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2008/09 AHSMC Part 1

All 16 problems. Take it as a timed test — 1:20:00 on the clock, scored the way the AMC is — or read through the problems and open any of them for its worked solution.

16 problems · 6 points correct, 1.5 for blank, 0 for wrong

  1. The numbers mm and nn are related by m=9n5+32m = \dfrac{9n}{5} + 32. If nn is an integer between 11 and 9999, the number of corresponding values of mm which are also integers is

  2. When the positive integers aa, bb and cc are divided by 1313, the respective remainders are 99, 77 and 1010. When a+2b+3ca + 2b + 3c is divided by 1313, the remainder is

  3. A polygon has area greater than 00. All side lengths are integers, the largest of which is 1010. The smallest possible perimeter of this polygon is

  4. Let ff and gg be functions such that f(x)=g(2x)f(x) = g(2x) and g(x)=2f(x)g(x) = 2f(x) for all real numbers xx. If g(2)=3g(2) = 3, the value of f(12)f\bigl(\dfrac{1}{2}\bigr) is

  5. If a certain positive integer is divided by 77, the remainder is 66. If it is divided by 44, the remainder is 11. The remainder when it is divided by 2828 is

  6. A building is in the shape of a right circular cylinder, with mirrors for its interior wall. A horizontal ray starts from a point on the wall, reflects off the wall exactly 1111 times and returns to its starting point for the first time. The number of possible directions along which it may have started is

  7. For a real number t≥0t \ge 0, ∣t∣=t|t| = t, and for a real number t<0t < 0, ∣t∣=−t|t| = -t. The number of real numbers xx satisfying ∣∣∣∣∣x−1∣−2∣−3∣−4∣−5∣=0|||||x - 1| - 2| - 3| - 4| - 5| = 0 is

  8. A rectangular box has integral dimensions and volume 20082008 cubic centimetres. In square centimetres, the minimum value of its surface area is

  9. The positive integers aa and bb are such that there are exactly 1010 integers greater than aa and less than bb, and exactly 10001000 integers greater than a2a^2 and less than b2b^2. The value of bb is

  10. Linda is walking at constant speed halfway between two parallel train tracks. On each track is a train of the same length. They are approaching Linda from different directions, both at VV kilometres per hour. The one going the same way as Linda takes t1t_1 seconds to pass her, while the other takes t2t_2 seconds to pass her. In kilometres per hour, Linda's walking speed is

  11. In base 1010, the positive integer aa has 22 digits, the positive integer bb has aa digits and the positive integer cc has bb digits. The smallest possible value for cc is

  12. Of the eight members of a Sports Club, two are senior boys, two are senior girls, two are junior girls and two are junior boys. An official team is of size four, and must consist of two seniors and two juniors, as well as two girls and two boys. The number of different official teams is

  13. On a vertical wall are drawn four geometric figures with equal area. The first is an equilateral triangle with a side along the floor. The second is an isosceles right triangle with one of the short sides along the floor. The third is a square with a side along the floor. The fourth is a circle tangent to the floor. The figure which reaches the highest point above the floor is

  14. The sum of the fifth powers of the roots of x3−3x+1=0x^3 - 3x + 1 = 0 is

  15. A country has 100100 cities numbered from 11 to 100100. For all m<nm < n, there is a road linking the mm-th and the nn-th city if and only if nm\dfrac{n}{m} is a prime number. One can travel in either direction on a road. The minimum number of roads one needs to use to go from the 9999th city to the 100100th city is

  16. In each lottery ticket, you choose two of the numbers 11, 22, 33, 44 and 55. Eventually, two of these five numbers will be drawn. Your ticket wins if neither of the numbers drawn are chosen on your ticket. The smallest number of tickets you must have in order to guarantee that at least one of them wins is

0 of 16 answered. Each problem left blank still scores 1.5 points.