Problem #PRU-78661

Problems Methods Pigeonhole principle Pigeonhole principle (angles and lengths) Set theory and logic Set theory Union, intersection, and set difference
 12–14  3.0

Problem

In a corridor of length 100 m, 20 sections of red carpet are laid out. The combined length of the sections is 1000 m. What is the largest number there can be of distinct stretches of the corridor that are not covered by carpet, given that the sections of carpet are all the same width as the corridor?