Question 339279
Let x be the amount of 65% solution. 
Let y be the amount of 20% solution.
1.{{{x+y=300}}}
.
.
.
{{{65x+20y=45(300)}}}
{{{65x+20y=13500}}}
2.{{{13x+4y=2700}}}
From eq. 1,
{{{y=300-x}}}
Substitute into eq. 2,
{{{13x+4(300-x)=2700}}}
{{{13x+1200-4x=2700}}}
{{{9x=1500}}}
{{{highlight(x=500/3)}}}
From eq. 1,
{{{y=900/3-500/3}}}
{{{highlight(y=400/3)}}}