Its easy to solve partitive proportions. Assume there exists a relationship between two entities in the ratio $1:4$ from a total measure of 300.
To solve partitive proportion, add the two parts as coefficients of some unknown variable $x$ to balance the relationship:
$1x+4x=300$
$5x=300$
$x=60$ and $4x=240$
Therefore the 300 units was divided in the ratio $1:4$ and it resulted in 60 units and 240 units respectively.