Question 1104318
One could only assume you mean mass per mass.


Only doing ONE example, and you figure the others.


30% sugar syrup from 7 grams of sugar:
Adding x GRAMS of water,
{{{75/(75+x)=0.30}}}
-
{{{75=0.3(x+75)}}}
{{{75=0.3x+22.5}}}
{{{0.x=(75-22.5)/0.3}}}
{{{x=175}}}


Total mass of these two materials will be {{{75+175=250}}} grams.