Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
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?

### Response:
If gilled mushrooms are rare, with only one for every nine spotted mushrooms, then there is 1 / 9 = 0.1 of a gilled mushroom for every spotted mushroom.
If the fallen log had 30 mushrooms growing on its side, then there were 0.1 * 30 = <<30*0.1=3>>3 gilled mushrooms on the fallen log’s side.
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