The part is 37.5 and the whole is 30. You need to find the percent.

Let n represent the percent.

Part = percentwhole

           (Substitute part = 37.5 and whole = 30)

      (Divide each side by 30)

               (Cancel common terms)

                  (Divide: )

     (Multiply with 100 and add percent sign)

                (Multiply: )

37.5 is 125 of 30.