Question 768077
f is volume of cofFee
r is volume of cReam
total volume of both together = f+r.
want 0.20 cream/(cream&coffee)


{{{r/(f+r)=0.2}}}


Now, f=300 ml. and r is unknown.  Find r.
{{{r=0.2(f+r)}}}
{{{r=0.2f+0.2r}}}
{{{r-0.2r=0.2f}}}
{{{r(1-0.2)=0.2f}}}
{{{0.8r=0.2f}}}
{{{highlight(r=(1/4)f)}}}
{{{highlight(r=300/4=75)}}} ml. of cream