document.write( "Question 938682: One type of candy sells for $2 per pound and another type sells for $3 per pound. An order for 18 pounds costs $47. How much of each type of candy was purchased?\r
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Algebra.Com's Answer #571866 by mathmate(429)\"\" \"About 
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Given:
\n" ); document.write( "Type A candy = $2 / lb
\n" ); document.write( "Type B candy = $3 / lb
\n" ); document.write( "18 pounds total cost $47.
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\n" ); document.write( "Solution method 1: using system of two equations,
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\n" ); document.write( "A,B = respective weight of each candy purchased in pounds.
\n" ); document.write( "A+B=18....(1)
\n" ); document.write( "2A+3B=47....(2)
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\n" ); document.write( "Solve by substitution
\n" ); document.write( "A=18-B....(1a)
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\n" ); document.write( "substitute (1a) in (2)
\n" ); document.write( "2(18-B)+3B=47....(3)
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\n" ); document.write( "Solve for B
\n" ); document.write( "36-2B+3B=47
\n" ); document.write( "B=47-36=11....(4)
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\n" ); document.write( "substitute (4) into (1a)
\n" ); document.write( "A=18-B=18-11=7
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\n" ); document.write( "Answer: 7 lbs of A and 11 lbs of B were purchased.
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\n" ); document.write( "Check: 7*2+11*3=$47, ok.
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\n" ); document.write( "Method 2: mental reasoning
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\n" ); document.write( "Given:
\n" ); document.write( "Type A candy = $2 / lb
\n" ); document.write( "Type B candy = $3 / lb
\n" ); document.write( "18 pounds total cost $47.\r
\n" ); document.write( "\n" ); document.write( "step 1: If all 18 lbs were type A, it would have cost $2*18=$36
\n" ); document.write( "step 2: There is an excess cost of $47-$36 = $11,
\n" ); document.write( " so number of pounds of type B purchased = $11/($3-$2)=11 lbs
\n" ); document.write( "step 3: weight of type A purchased = 18-11=7 lbs.
\n" ); document.write( "Answer: 7 lbs of A and 11 lbs of B.
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