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)![]() ![]() You can put this solution on YOUR website! 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. \n" ); document.write( " \n" ); document.write( "Solution method 1: using system of two equations, \n" ); document.write( "================================================ \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) \n" ); document.write( " \n" ); document.write( "Solve by substitution \n" ); document.write( "A=18-B....(1a) \n" ); document.write( " \n" ); document.write( "substitute (1a) in (2) \n" ); document.write( "2(18-B)+3B=47....(3) \n" ); document.write( " \n" ); document.write( "Solve for B \n" ); document.write( "36-2B+3B=47 \n" ); document.write( "B=47-36=11....(4) \n" ); document.write( " \n" ); document.write( "substitute (4) into (1a) \n" ); document.write( "A=18-B=18-11=7 \n" ); document.write( " \n" ); document.write( "Answer: 7 lbs of A and 11 lbs of B were purchased. \n" ); document.write( " \n" ); document.write( "Check: 7*2+11*3=$47, ok. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Method 2: mental reasoning \n" ); document.write( "========================== \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. \n" ); document.write( " |