document.write( "Question 1117356: . The cost of petrol rises by 2 cents a liter. last week a man bought 20 liters at the old price. This week he bought 10 liters at the new price. Altogether, the petrol costs $9.20. What was the old price for 1 liter? \n" ); document.write( "

Algebra.Com's Answer #732408 by ikleyn(52943) $\"\"$ $\"About$

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document.write( "20x + 10*(x+2) = 920   cents,   where x is old price in cents for 1 liter.\r\n" );
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document.write( "20x + 10x + 20 = 920\r\n" );
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document.write( "30x = 920-20\r\n" );
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document.write( "30x = 900  ====>  x =  = 30.\r\n" );
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document.write( "Answer.  The old price for one liter of petrol was $0.30 per liter.\r\n" );
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