Question 152639
Given {{{7g + 11c + 5s + 3c = 980}}}
{{{g = 3c}}}  ---> {{{c = g/3}}} 
{{{g = 0.5s}}} -->  {{2g = s}}}
{{{g = 0.25c}}} --> {{{4g = c}}}

Use substitution
{{{7g + 11c + 5s + 3c = 980}}}
{{{7g + 11*g/3 + 5*2g + 3*4g = 980}}}
{{{7g + 11g/3 + 10g + 12g = 980}}}
{{{(29+11/3)g = 980}}}
{{{(87+11)g/3  = 980}}}
{{{g = (980*3)/98}}}
{{{g = 30}}}

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