Question 835514
x count rooms without kitchen
y count rooms WITH kitchen


{{{x+y=200}}}, because all rooms occupied;
{{{80x+100y=17000}}}, that night's revenue.


Simplifying the revenue equation, {{{8x+10y=1700}}}
{{{4x+5y=850}}}


Use the system:
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x+y=200
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4x+5y=850
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Try Elimination.  Multitply the room count equation by 4, and....