document.write( "Question 1090625: Justin has a total of 16 Singapore and Malaysian stamps. If he exchanges every Singapore stamp for 2 Malaysian stamps, he will have 21 Malaysian stamps. How many Singapore and Malaysian stamps does Justin have? \n" ); document.write( "
Algebra.Com's Answer #705094 by Edwin McCravy(20059)\"\" \"About 
You can put this solution on YOUR website!
Justin has a total of 16 Singapore and Malaysian stamps.
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S + M = 16
If he exchanges every Singapore stamp for 2 Malaysian stamps,
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1.  He first would subtract the S Singapore stamps, and has left only\r\n" );
document.write( "M Malaysian stamps\r\n" );
document.write( "2.  Then second, he would replace the S Singapore stamps with 2S\r\n" );
document.write( "Malaysian stamps.
he will have 21 Malaysian stamps.
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document.write( "3.  Then he would have the M Malaysian stamps he had at the start\r\n" );
document.write( "PLUS the 2S Malaysian stamps he traded for, or M + 2S.
How many Singapore and Malaysian stamps does Justin have?
4. We set that quantity equal to 21.\r\n" );
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document.write( "So M + 2S = 21\r\n" );
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document.write( "Solve that for M\r\n" );
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document.write( "        M = 21-2S\r\n" );
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document.write( "Substitute 21-2S for M in\r\n" );
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document.write( "      S + M = 16\r\n" );
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document.write( "S + (21-2S) = 16   \r\n" );
document.write( "S + 21 - 2S = 16\r\n" );
document.write( "    -S + 21 = 16\r\n" );
document.write( "         -S = -5\r\n" );
document.write( "          S = 5\r\n" );
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document.write( "Substitute 5 for S in\r\n" );
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document.write( "        M = 21-2S\r\n" );
document.write( "        M = 21-2(5)\r\n" );
document.write( "        M = 21-10\r\n" );
document.write( "        M = 11\r\n" );
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document.write( "So he has 5 Singapore stamps and 11 Malaysian stamps.\r\n" );
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document.write( "Checking:  He has 5+11 stamps, which when added gives 16.\r\n" );
document.write( "That checks! If he trades the 5 Sinapore stamps for twice\r\n" );
document.write( "as many, or 10, Malaysian stamps, then he'll have 10 more\r\n" );
document.write( "Malaysian stamps than the 11 he started with, or 21 Malaysian\r\n" );
document.write( "stamps.  That also checks.\r\n" );
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document.write( "Edwin

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