Explain simply why 3 is the correct answer to: A certain kind of wild mushroom has either spots or gills, but never both. Gilled mushrooms are rare, with only one growing for every nine spotted mushrooms that grow. A fallen log had 30 mushrooms growing on its side. How many gilled mushrooms were on the fallen log's side?. Explanation:
There is 1 gilled mushroom for every 1 + 9 = 10 mushrooms. Thus, there were 30 / 10 = 3 gilled mushrooms on the fallen log's side.