Total number of students = 31
19 prefer white bread
31 - 19 prefer wheat bread ==> 31- 19 = 12 prefer wheat bread
Relations:
Part to part:
Relation between the number of students that prefer wheat bread to the number of students that prefer white bread:
Ratio: 12/19
Part to part:
Relation between the number of students that prefer white bread to the number of students that prefer white bread:
Ratio: 19/12
Part to whole:
Relation between the number of students that prefer wheat bread to the total number of students:
Ratio: 12/31
Part to whole:
Relation between the number of students that prefer white bread to the total number of students:
Ratio: 19/31