You can put this solution on YOUR website! ok 7 mph in 1 hour 30 minutes.
We can get rid of the 1 hour bit first, so by walking 7 miles an hour in an hour you have walked 7 miles.
Now for the 30 minutes part, simply divide the 7 miles you walk in an hour by 2 to get 3.5miles. Add this to the 7 miles you already had and you have 11.5 miles.
So you have walked 11.5 miles.