Question 1112324
x of the 20c coins
y of the 50c coins


{{{system(20x=50y,x-y=300)}}}

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{{{2x=5y,x=y+300}}}

{{{2(y+300)=5y}}}

{{{2y+600=5y}}}

{{{3y=600}}}

{{{highlight(y=200)}}}----------the number of the 50c coins