Well, if he walked a total of 11 miles, and he ran a total of twice 11 miles + 2, then we can write it out like this. Note: R = miles ran.
R = (11 * 2) + 2
If you do this equation, you end up with
R = (11 * 2 = 22) + 2
R = 22 + 2
R = 24
I hope this helps.