Two students standing apart in a classroom have a gravitational force of attraction between them of 3.20 x 10-8 n. if one student has a mass of 50.0 kg and the other has a mass of 60.0 kg

I have a hunch that you want to know the distance
between the students.    It's just a hunch.

Here's the formula for the force of gravity between 2 masses:

               Force of gravity =  G · m₁ · m₂ / D²

Take the numbers given in the question, write them into the formula,
and solve it for 'D'.

If you just want the answer and don't care to see the work,
then skip to the bottom line now.

To see every step along the way, keep reading:
 

           ' F '                              ' G '                   ' m₁ '      ' m₂ '
    3.2 x 10⁻⁸ nt  =  (6.67 x 10⁻¹¹ nt-m²/kg²) (50 kg) (60 kg) / D²

    3.2 x 10⁻⁸ nt = (6.67 x 10⁻¹¹ x 50 x 60) (nt-m²) / D²

         D²  =  (6.67 x 10⁻¹¹ x 50 x 60) (nt-m²) / (3.2 x 10⁻⁸ nt)

         D²  =  6.253125 m²

         D  =   √6.253125 m²  =  2.5 m      (rounded)