How to generate different random numbers with same function c#

In my program, i have the following codes in 2 classes:

Random Rand = new Random ();
        _x = (Rand.Next (0, 31));
        _y = (Rand.Next (0, 23));

The problem is when the program runs. Both the classes generates the exact same number. How can I code this in a way that both of the coordinates (_x & _y) are generated differently so i can have two different coordinates?

I am using C# in Xamarin Studio.