Question 903820
Two types of audience members:  Adults and all others.  "Adults" will not include Senior Citizens.


x count of adults
y count of all others which is children under 12 and senior citizens combined.


The description gives these equations:
x+y=100, and 6x+4y=450


The system after simplifying the money equation is
{{{highlight_green(system(x+y=100,3x+2y=225))}}}


Starting with Elimination Method will be easiest; multiply the ticket count equation by 2 and subtract one equation from the other.


{{{3x+2y-(2x+2y)=225-200}}}
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