Question 1068468
{{{Q=9x}}}
{{{D=3x}}}
{{{N=x}}}
{{{25Q+10D+5N=1820}}}
Substituting,
{{{25(9x)+10(3x)+5x=1820}}}
{{{225x+30x+5x=1820}}}
{{{260x=1820}}}
{{{x=7}}}
So,
{{{Q=9(7)=63}}}
{{{D=3(7)=21}}}
{{{N=7}}}