Math Challenge Adds Up to Big Rewards

July 8, 2012 | CUNY Matters, The University

The annual CUNY Math Challenge — sponsored by the Office of Academic Affairs and the CUNY Institute for Software Design and Development, and supported by the Office of the Chancellor — this year rewarded nine math whizzes with cash prizes ranging from $500 up to a grand prize of $2,500.

The top award went to Queens College freshman Cheuk Hong Lam. Two seniors, Damon Cham of New York City College of Technology and Juncheng Zhang of Baruch College, won second place awards. Third place went to Brooklyn College junior Jason Reed. City College senior Samuel (Kyuedong) Kim and Baruch College junior Aleksandr Yaroslavsky placed fourth. Fifth prize went to City College senior Yin Choi Cheng, Queensborough Community College sophomore Dan Zheng and Baruch College sophomore Xiao Zheng.

At the awards ceremony, two Hunter College professors of mathmatics and statistics — Sandra Clarkson and W.H. Williams — received the Chancellor’s Award for Excellence in Undergraduate Mathmatics Instruction.

How Would You Do in the Math Challenge?

Match wits with the ace students: See if you can solve this question from Round 1 of the 2012 Math Challenge.

Problem:

Two plants, a rose and a jasmine, grow up and around a cylindrical tree trunk. They start from the same point at the foot of the tree, but the rose goes clockwise and the jasmine counterclockwise around the trunk. When the two plants meet at the first branch, the rose has made three circles around the trunk and the jasmine has made five circles. How many times did the plants cross between the foot of the tree and the first branch? (Answer below)

Math Problem Solution: They cross seven times between the ground and the first branch. Imagine that the tree trunk is sliced into very thin disks, and rotate each of these disks clockwise by just enough to unwind the jasmine and make it grow straight up the trunk. The disk at the first branch is rotated clockwise by five complete revolutions. The rose must make eight circles around the rotated tree trunk (eight being the sum of three circles by the rose and five complete rotations of the topmost disk.) These circles cross the straight path of the jasmine seven times between the ground and the first branch.