A Partitive Proportion, or proportion by parts, describes a whole amount being divided or distributed into two or more unequal parts.

EXAMPLE:

The ratio of boys to girls in a class is 3:5, If there are 48 students in the class, how many boys and girls are there?

Since we don't know the constant of proportionality. we let that x which means that

3x is the number of Boys

5x is the number of Girls

3x + 5x = 48

8x = 48

x = 6