document.write( "Question 107937: What amount of each mixture, one 95% alcohol and the other 15% alcohol, must be used to make 10 liters of a mixture which is 45% alcohol? what equation or equations will express this problem? I was thinking it would be this equation: 0.95x+0.15x=0.45 \n" ); document.write( "
Algebra.Com's Answer #78680 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
AT LEAST YOU GAVE IT A SHOT BUT YOU ARE GENERALLY FAR BETTER OFF IF YOU LAY OUT THE WORD PROBLEMS (WHAT EQUALS WHAT) AS I HAVE DONE BELOW.\r
\n" ); document.write( "\n" ); document.write( "Let x=the amount of 95% alcohol mixture
\n" ); document.write( "Then 10-x=amount of 15% alcohol mixture\r
\n" ); document.write( "\n" ); document.write( "Now we know that the amount of pure alcohol in the 95% mixture (0.95x) plus the amount of pure alcohol in the 15% mixture (0.15(10-x)) has to equal the amount of pure alcohol in the 45% mixture (0.45*10). So our equation to solve is:\r
\n" ); document.write( "\n" ); document.write( "0.95x+0.15(10-x)=0.45*10 get rid of parens (distributive law)
\n" ); document.write( "0.95x+1.5-0.15x=4.5 subtract 1.5 from both sides\r
\n" ); document.write( "\n" ); document.write( "0.95x+1.5-1.5-0.15x=4.5-1.5 collect like terms\r
\n" ); document.write( "\n" ); document.write( "0.80x=3 divide both sides by 0.80\r
\n" ); document.write( "\n" ); document.write( "x=3.75 liters-----------amount of 95% alcohol mixture
\n" ); document.write( "10-x=10-3.75= 6.25 liters-----------------amount of 15% alcohol mixture\r
\n" ); document.write( "\n" ); document.write( "CK
\n" ); document.write( "0.95*3.75+0.15*6.25=0.45*10
\n" ); document.write( "3.5625+0.9375=4.5\r
\n" ); document.write( "\n" ); document.write( "4.5=4.5\r
\n" ); document.write( "\n" ); document.write( "ANOTHER WAY\r
\n" ); document.write( "\n" ); document.write( "Let x=amount of 95% alcohol mixture
\n" ); document.write( "And let y=amount of 15% alcohol mixture
\n" ); document.write( "Now we are told that:\r
\n" ); document.write( "\n" ); document.write( "x+y=10----------------------eq1
\n" ); document.write( "We also know that:\r
\n" ); document.write( "\n" ); document.write( "0.95x+0.15y=0.45*10------------------eq2\r
\n" ); document.write( "\n" ); document.write( "From eq1, y=10-x. Substitute this into eq2 and we get:\r
\n" ); document.write( "\n" ); document.write( "0.95x+0.15(10-x)=4.5-----------------same equation as before.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Hope this helps---ptaylor\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );