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

### Instruction:
Enrico owns a rooster farm, he sells each rooster for $0.50 per kilogram. He was able to sell a 30-kilogram rooster and a 40-kilogram rooster, how much money was he able to earn?

### Response:
Enrico was able to sell a 30-kilogram rooster for $0.50x30=$<<30*0.5=15>>15.
And he was able to sell a 40-kilogram rooster for $0.50x40=$<<0.50*40=20>>20.
Therefore, he was able to earn $15+$20=$<<15+20=35>>35 for the two roosters.
#### 35