document.write( "Question 516802: Allan bought some 5 cent stamps and some 20 cent stamps. The entire purchase was $7 he bought three times as many f cent stamps as 20 cent stamps how many of each stamps did he buy? \n" ); document.write( "

Algebra.Com's Answer #344505 by oberobic(2304) $\"\"$ $\"About$

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x = number of five-cent stamps
\n" ); document.write( "5x = value of the five-cent stamps in cents
\n" ); document.write( "y = number of twenty-cent stamps
\n" ); document.write( "20y = value of the twenty-cent stamps in cents
\n" ); document.write( ".
\n" ); document.write( "5x +20y = 700 cents
\n" ); document.write( ".
\n" ); document.write( "three times as many 5-cent stamps as 20-cent stamps
\n" ); document.write( "x = 3*y
\n" ); document.write( ".
\n" ); document.write( "substitute
\n" ); document.write( ".
\n" ); document.write( "5(3y) +20y = 700
\n" ); document.write( "15y + 20y = 700
\n" ); document.write( "35y = 700
\n" ); document.write( "y = 20
\n" ); document.write( ".
\n" ); document.write( "x =3y = 3(20) =60
\n" ); document.write( ".
\n" ); document.write( "check the value
\n" ); document.write( ".
\n" ); document.write( "5(60) = 300 cents
\n" ); document.write( "20(20) = 400 cents
\n" ); document.write( "300+400 = 700 cents
\n" ); document.write( "correct
\n" ); document.write( ".
\n" ); document.write( "Answer: He bought 20 twenty-cent stamps and 60 five-cent stamps.
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