April 27–May 3, 2010

Problem

Let ABCD be a quadrilateral, whose diagonals intersect at O. The triangles AOB, BOC, COD, have areas 1,2,4, respectively.
What is the area of the triangle AOD? What type of quadrilateral is ABCD?

Solution

here

List of solvers

Lloyd Sakazaki, Aparna Khare, Lincoln Atkinson, Derek Redfern, Gary Mager, Mukund Tirumalai, Kevin Sonnanburg, Jason Shaw, Joshua Lim, Jonathan Cross, Peiyush Jain, Brett Kleinschmidt, Crispin Pereira, Mike Goodman.

Jason Shaw wins the prize!