Priya and Riya travel from their home to their respective colleges which are at a distance of 20 km and 25 km respectively. They leave home at the same time and reach their colleges at 8:30
A.M. One day, they decided to go to each other's college, so Priya started 9 minutes earlier than Riya to reach the college at the same time. Find the speed of Priya.

Distance covered by Priya and Riya = 20 km and 25 km, respectively.
Since, both of them reached their respective places at same time.
Therefore, ratio of speeds of Priya and Riya = 20:25 = 4:5.
Let the speeds of Priya and Riya be 4x km/hr and 5x km/hr, respectively.
Time taken by Priya to reach her place on the day of interchange = 25/4x hours.
Time taken by Riya to reach her place on the day of interchange = 20/5x hours.
ATQ, (25/4x) – (20/5x) = 9/60.
Or, 6.25/x - 4/x = 0.15.
Or, 2.25/x = 0.15.
Or, x = 15.
So, speed of Priya = 4x = 60 km/hr.
Hence, the correct answer is D.