Problem A. 536. (May 2011)
A. 536. The positive real numbers a, b, c, d satisfy a+b+c+d=abc+abd+acd+bcd. Prove that
(5 pont)
Deadline expired on June 10, 2011.
Statistics:
4 students sent a solution. 5 points: Backhausz Tibor, Frankl Nóra, Janzer Olivér, Nagy 235 János.
Problems in Mathematics of KöMaL, May 2011