Juan walks 3.5 miles in 56 minutes. How long will it take him to walk 1 mile?

To find out how long it will take Juan to walk 1 mile, we need to divide the time he takes to walk 3.5 miles by 3.5.

So, the time it will take him to walk 1 mile is 56 minutes / 3.5 = <<56/3.5=16>>16 minutes. Answer: \boxed{16}.