10/16 and 50/75 and 18/32 and 31/93

1.) 10/16 
The greatest common factor of this fraction is 2, so divide the numerator and denominator by 2.
Final 5/8

2.) 50/75 
The greatest common factor of this fraction is 25, so divide the numerator and denominator by 25.
Final 2/3

3.) 18/32
The greatest common factor of this fraction is 2, so divide the numerator and denominator by 2.
Final 9/16

4.) 31/93
You cannot factor anything into 31, therefore, the fraction stays the same.
Final 31/93 *Does not change.