Establish a rectangular coordinate system. The x-axis represents the time when A arrives, and the y-axis represents the time when B arrives. With 10 as the origin, the value of any point in a square with a side length of 30 can indicate the arrival time of both parties (in this case, a square with a side length of 3).

The points where two people meet in 15 minutes are as follows:

Then divide the shadow area by the whole area, and the probability of meeting is 0.75.