document.write( "Question 1158749: An electronics company makes two types of switches. Type A takes 3 minutes to make and requires $2 worth of materials. Type B takes 4 minutes to make and requires $4 of materials. In the latest production batch, it took 27 hours to make these switches, and the materials cost $1400. How many of each type of switch were made? \n" ); document.write( "

Algebra.Com's Answer #781731 by ikleyn(52788) $\"\"$ $\"About$

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document.write( "Let \"a\" be the number of the type A items, and let \"b\" be the number of the type B items.\r\n" );
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document.write( "Then from the condition, you have these two equations\r\n" );
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document.write( "    3a + 4b = 1620 minutes     (1)    (1620 = 27 hours * 60 minutes, the time spent)\r\n" );
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document.write( "    2a + 4b = 1400 dollars     (2)    (Cost of the material).\r\n" );
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document.write( "To solve the system of equations, from equation (2) subtract equation (1). You will get\r\n" );
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document.write( "    3a - 2a = 1620 - 1400,   or\r\n" );
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document.write( "     a      = 220.\r\n" );
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document.write( "Next, substitute the found valu of a= 220 into equation (2). You will get\r\n" );
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document.write( "    2*220 + 4b = 1400,\r\n" );
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document.write( "    4b = 1400 - 2*220 = 960\r\n" );
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document.write( "     b                = 960/4 = 240.\r\n" );
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document.write( "ANSWER.  220 items of the type A and 240 items of the type B.\r\n" );
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