Question 1138607
Only a start -


p pit
h house
b balcony


{{{system(p+h+b=1800,p+h=7b,20p+35h+50b=48000)}}}


Divide revenue equation by 5:
{{{4p+7h+10b=9600}}}



System of Equations:
{{{system(p+h+b=1800,p+h-7b=0,4p+7h+10b=9600)}}}





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you may like to try  https://matrix.reshish.com/cramer.php  .


p = 1225
h = 350
b = 225