Question 483547
Let x the large size rings
Let y the regular size rings
There were sold 120 rings, then {{{x+y=120}}}
The total receipts from the sale of 120 rings was $15,060, so {{{145x+115y=15060}}}
The system of equations
{{{system(x+y=120, 145x+115y=15060)}}}
From the first equation {{{y=120-x}}}
Substitute into the second equation {{{145x+115(120-x)=15060}}}
{{{145x+13800-115x=15060}}}
{{{30x=1260}}}
{{{x=1260/30}}}
{{{x=42}}}the large size rings were sold
{{{y=120-42=78}}}the regular size rings were sold