document.write( "Question 805550: 2 black and 3 read pen bought for Rs. 23 then 3 black and 2 read pen bought for Rs. 16 how much paid for 1 black pen? \n" ); document.write( "
Algebra.Com's Answer #485362 by rothauserc(4718)\"\" \"About 
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1) 2b +3r = 23
\n" ); document.write( "2) 3b +2r = 16
\n" ); document.write( "solve second equation for r
\n" ); document.write( "2r = 16 -3b
\n" ); document.write( "r = 8 -3b/2
\n" ); document.write( "substitute for r in first equation
\n" ); document.write( "2b +3*(8 -3b/2) = 23
\n" ); document.write( "2b +24 -9b/2 = 23
\n" ); document.write( "4b/2 -9b/2 = -1
\n" ); document.write( "-5b/2 = -1
\n" ); document.write( "-5b = -2
\n" ); document.write( "b = 2/5
\n" ); document.write( "b = .40 rs
\n" ); document.write( "now check answer
\n" ); document.write( "3*(.40) +2r = 16
\n" ); document.write( "2r = 16 - 1.20
\n" ); document.write( "r = 7.4
\n" ); document.write( "substitute in first equation
\n" ); document.write( "2*(.40) +3*(7.40) = 23
\n" ); document.write( ".80 + 22.20
\n" ); document.write( "answer checks\r
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