document.write( "Question 1120158: At a local garage sale, Christ bought 4 gardening magazines and 3 mugs for $8.70; Sarah bought 5 magazines , 2 mugs and 3 refrigerator magnets for $12.35; and Steve bought 2 magazines, 4 ceramic mugs and 4 refrigerator magnets for $15.50. What was the price of each refrigerator magnet? \n" ); document.write( "
Algebra.Com's Answer #735849 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Yes, there are ways to solve systems of equations using calculators of various sorts. But solving them with pencil and paper is a useful skill.... \n" ); document.write( "The statement of the problem yields three equations: \n" ); document.write( "(1) 4x+3y = 8.70 \n" ); document.write( "(2) 5x+2y+3z = 12.35 \n" ); document.write( "(3) 2x+4y+4z = 15.50 \n" ); document.write( "Since one of the equations has only two of the variables, very probably the best way to start solving the system is to eliminate the third variable from the other two equations, yielding a system of two equation in two unknowns. \n" ); document.write( "20x+8y+12z = 49.40 \n" ); document.write( "6x+12y+12z = 46.50 \n" ); document.write( "14x-4y = 2.90 \n" ); document.write( "Now eliminate y between this equation and equation (1). \n" ); document.write( "16x+12y = 34.80 \n" ); document.write( "42x-12y = 8.70 \n" ); document.write( "58x = 43.50 \n" ); document.write( "x = 43.50/58 = 0.75 \n" ); document.write( "4(.75)+3y = 8.70 \n" ); document.write( "3y = 5.70 \n" ); document.write( "y = 1.90 \n" ); document.write( "2(.75)+4(1.90)+4z = 15.50 \n" ); document.write( "4z = 6.40 \n" ); document.write( "z = 1.60 \n" ); document.write( "The cost of each refrigerator magnet, z, was $1.60. \n" ); document.write( " \n" ); document.write( " |