KöMaL 2019 B4998

A set of small plastic figures used as a visual aid in primary-school mathematics consists of $48$ pieces. The figures can be classified according to four different attributes: their size may be large or small, they may have or not have a hole in the middle, their colour may be red, yellow, blue or green, and their shape may be circular, square or triangular. Every possible combination of the four properties (e.g. small, blue circular disc with a hole) occurs exactly once. How many pieces $x$ are there in the set, such that there exists a piece $y$ for which the two conditions below both hold? 1. If $x$ is red or has no hole, then $y$ is a small yellow square. 2. If $y$ is small or blue, then $x$ is a green triangle or some figure without a hole.