Question 69818
Let x= amount of $12 coffee

Then 100-x=amount of $9 coffee

Value of $12 coffee (12x) plus value of $9 coffee (9(100-x)) has to equal value of final mixture $11.25(100).  So our equation to solve is:


12x+9(100-x)=11.25(100)  get rid of parens

12x+900-9x=1125  subtract 900 from both sides

3x=1125-900

3x=225 divide both sides by x

x=75 lbs----------------------------------amount of $12 coffee

100-x=100-75=25 lbs---------------------------amount of $9 coffee

Ck

75*12+25*9=100*(11.25)

900+225=1125

1125=1125



Hope this helps------ptaylor