Colin ran his first mile in 6 minutes.
He ran his next two miles in 5 minutes each, so that's a total of 2 * 5 = 10 minutes.
He finished his 4th mile in 4 minutes.
The total time it took him to run 4 miles is 6 + 10 + 4 = 20 minutes.
To find the average time per mile, we divide the total time by the number of miles, so 20 / 4 = 5 minutes.
The average time it took him to run a mile is 5 minutes.
#### 5
The answer is: 5
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Colin ran his first mile in 6 minutes.  He ran his next two miles in 5 minutes each and finished his 4th mile in 4 minutes.  What was the average time it took him to run a mile?

### Answer:
