Answer:
21 minutes and 40 seconds
Explanation:
A couple ways to do these, but probably the most straightforward is to find their walking rate:
0.5 miles in 10 minutes is 0.05 miles per minute
Then divide 1 1/12 miles by 0.05 miles per minute to get minutes, the amount of time it takes them. (Are you sure it's 1 & 1/12 miles? Because that's sort of a weird fraction.)
Put it in your calculator and you'll get 21.6666 minutes, which they'll probably want you to state as 21 2/3 minutes, or 21 minutes and 40 seconds.