Question 935923
{{{H+D+C+S=234}}}
{{{H=20+D}}}
{{{C=53+D}}}
{{{S=71+D}}}
Substituting into the first equation,
{{{(20+D)+D+(53+D)+(71+D)=234}}}
{{{4D+144=234}}}
{{{4D=90}}}
{{{D=22.5}}}
Then,
{{{H=20+22.5=42.5}}}
{{{C=53+22.5=75.5}}}
{{{S=71+22.5=93.5}}}