document.write( "Question 390126: Macadamia nuts cost $.90 per ounce, peanuts cost $.30 per ounce, an cashews cost $1.30 per ounce. You want a 20- ounce mixture of macadamia nuts, peanuts, and cashews that costs $.68 per ounce. If the combined weight of the macadamia nuts and cashews equals the wight of the peanuts, how many ounces of each nut should be used? \n" ); document.write( "
Algebra.Com's Answer #276637 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
Let x=amount of peanuts
\n" ); document.write( "y=amount of macadamia nuts
\n" ); document.write( "z=amount of cashews
\n" ); document.write( "x+y+z=20----------------------------------eq1
\n" ); document.write( "0.30x+0.90y+1.30z=20*0.68=13.6---------------eq2
\n" ); document.write( "y+z=x--------------------------------------eq3
\n" ); document.write( "substitute y+z=x into eq1 and we get
\n" ); document.write( "2x=20
\n" ); document.write( "x=10 oz-------------------------amount of peanuts needed
\n" ); document.write( "substitute x=10 into eq2 and eq3 and we get:
\n" ); document.write( "0.90y+1.30z=10.6----eq2a
\n" ); document.write( " y+z=10-----eq3a
\n" ); document.write( "multiply eq3a by 0.90 and then subtract eq 3a from eq2a and we get:
\n" ); document.write( "0.40z=1.6
\n" ); document.write( "z=4 oz---------------------amount of cashews needed
\n" ); document.write( "substitute z=4 into eq 3a and we get:
\n" ); document.write( "y=6 oz--------------------------amount of macadamias needed\r
\n" ); document.write( "\n" ); document.write( "CK
\n" ); document.write( "0.30*10+0.90*6+1.30*4=13.6\r
\n" ); document.write( "\n" ); document.write( "3+5.4+5.2=13.6
\n" ); document.write( "13.6=13.6\r
\n" ); document.write( "\n" ); document.write( "Hope this helps---ptaylor\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );