Given the task definition and input, reply with output. The task is to generate the correct answer for a given math problem.

Problem: total 30 cows 10 cow gives each 2 liter milk 10 cow gives each 3 / 4 liter milk 10 cow gives each 1 / 4 liter milk this is split into 3 son per each 10 cows & 10 liter milk how ?
10