If Lexie takes 20 minutes to run a mile, then Celia, who runs twice as fast, will take 20/2 = 10 minutes to run a mile.
To run 30 miles, Celia will take 10 minutes x 30 miles = 300 minutes.
#### 300
The answer is: 300
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
If Lexie takes 20 minutes to run a mile and Celia runs twice as fast as Lexie, how long, in minutes, will it take Celia to run 30 miles?

### Answer:
