document.write( "Question 1043905: Please help:\r
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document.write( "One canned juice drink is 15% orange juice; another is 5% orange juice. How many liters of each should be mixed together in order to get 10L that is 7% orange juice? \n" );
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Algebra.Com's Answer #659101 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Let \n" ); document.write( "x = amount of the juice drink that is 15% orange juice \n" ); document.write( "y = amount of the juice drink that is 5% orange juice \n" ); document.write( "both amounts are in liters (L)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "---------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have x liters from one can and y liters from another can. We mix them together and together they make 10 liters of juice. So x+y = 10 is our first equation.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have x liters of the 15% orange juice. The amount of pure orange juice is 0.15x liters.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have y liters of the 5% orange juice. The amount of pure orange juice is 0.05y liters.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In total, those amounts combine to 0.15x+0.05y. We want 10 liters of 7% orange juice. So we want 10*0.07 = 0.7 liters of pure orange juice.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Therefore, the two amounts must be the same (ie equal). So 0.15x+0.05y = 0.7 is the second equation\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "---------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "To summarize so far, we have these two equations\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x+y = 10 \n" ); document.write( "0.15x+0.05y = 0.7\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's focus on the first equation for now. Solve for y to get...\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x+y = 10\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x+y-x = 10-x ... subtract x from both sides\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 10-x\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now that y is isolated, we can plug this into the other equation\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.15x+0.05y = 0.7\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.15x+0.05( y ) = 0.7\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.15x+0.05( 10-x ) = 0.7 ... replace y with 10-x. Now solve for x.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.15x+0.05(10)+0.05(-x) = 0.7\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.15x+0.5-0.05x = 0.7\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.10x+0.5 = 0.7\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.10x+0.5-0.5 = 0.7-0.5\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.10x = 0.2\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0.10x/0.10 = 0.2/0.10\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 2\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We finally know the value of x. Use this to find y.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 10-x\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 10-2 ... replace x with 2\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 8\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "---------------------------------------------------------- \n" ); document.write( "----------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In the end, we found that x = 2 and y = 8. Recall that at the very top we stated that\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = amount of the juice drink that is 15% orange juice \n" ); document.write( "y = amount of the juice drink that is 5% orange juice\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so this means that we must mix 2 liters of the 15% juice drink with 8 liters of the 5% juice drink. \n" ); document.write( " \n" ); document.write( " |