A student is asked to find positive integer solutions to this equation:

2 * 3 √x = 5 √y

What is the smallest possible value of xy? (Please show working out, thank you.)

2 * 3 √x = 5 √y

6√x = 5√y
36x = 25y

Since 36 and 25 have no factors in common, we must have

x=25 and y=36