If it takes 10 people 10 days to shovel 10,000 pounds of coal, then the rate of shoveling is 10,000 pounds / (10 people * 10 days) = 100 pounds per person per day.
If half of these ten people are shoveling, that means 5 people are shoveling.
So, if the rate is 100 pounds per person per day, then 5 people can shovel 5 * 100 = 500 pounds per day.
If they need to shovel 40,000 pounds of coal, then it will take 40,000 pounds / 500 pounds per day = 80 days.
#### 80
The answer is: 80
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
If it takes 10 people 10 days to shovel 10,000 pounds of coal, how many days will it take half of these ten people to shovel 40,000 pounds of coal?

### Answer:
