X is between 6 and 8 o'clock? Y is from 7 to 9.
Form a square with a side length of 2 and an area of 4.
The so-called can't see the newspaper means that the time when people leave is less than the time when they deliver the newspaper, which is Y.
That is, the area under y=x in a square is an isosceles right triangle with waist length of 1 and area of 1/2.
So the probability is P=( 1/2)/4= 1/8.
The figure is as follows: