Final answer:
Three roosters can wake up 30 hens.
Step-by-step explanation:
To find out how many hens 3 roosters can wake up, we need to multiply the number of hens one rooster can wake up by the number of roosters. Since one rooster can wake up 10 hens, and there are 3 roosters, we can calculate it as: 10 hens/rooster * 3 roosters = 30 hens.