document.write( "Question 155228: kindly solve these problems for me:
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document.write( "1. Charles and Melanie are 100 km apart and are driving at constant speeds. If they drive toward each other, they will meet in 1 hr. If they drive in the same direction, he will overtake her in 5 hr. Find their speeds.
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document.write( "2. Wayne invested part of his money at 8% and the rest at 6%. The income from both investments totaled $2,000. If he interchanged his investments, his income would increase by $340. How much did he have in each investment? \n" );
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Algebra.Com's Answer #114351 by ankor@dixie-net.com(22740) You can put this solution on YOUR website! 1. Charles and Melanie are 100 km apart and are driving at constant speeds. \n" ); document.write( " If they drive toward each other, they will meet in 1 hr. If they drive in \n" ); document.write( " the same direction, he will overtake her in 5 hr. Find their speeds. \n" ); document.write( "; \n" ); document.write( "Let x = C's speed \n" ); document.write( "Let y = M's speed \n" ); document.write( ": \n" ); document.write( "When they are driving towards each other, their speeds are additive: \n" ); document.write( "Write a distance equation, Dist = time * speed \n" ); document.write( "1(x+y) = 100 \n" ); document.write( "x + y = 100 \n" ); document.write( "or \n" ); document.write( "y = (100-x) \n" ); document.write( ": \n" ); document.write( "Write another distance equation, when they go the same direction. \n" ); document.write( "C has to travel has to travel 100 further than M in the same time (5 hrs)\r \n" ); document.write( "\n" ); document.write( "5x - 100 = 5y \n" ); document.write( "Replace y with (100-x) \n" ); document.write( "5x - 100 = 5(100-x) \n" ); document.write( ": \n" ); document.write( "5x - 100 = 500 - 5x \n" ); document.write( ": \n" ); document.write( "5x + 5x = 500 + 100 \n" ); document.write( ": \n" ); document.write( "10x = 600 \n" ); document.write( ": \n" ); document.write( "x = 60 km/hr is C's speed \n" ); document.write( "Find M's speed \n" ); document.write( "y = 100 - 60 \n" ); document.write( "y = 40 km/hr is M's speed \n" ); document.write( ": \n" ); document.write( "Check solutions using the distance \n" ); document.write( "5*60 = 300 km \n" ); document.write( "5*40 = 200 km \n" ); document.write( "-------------- \n" ); document.write( "diff = 100 km \n" ); document.write( "; \n" ); document.write( ": \n" ); document.write( "2. Wayne invested part of his money at 8% and the rest at 6%. The income from \n" ); document.write( "both investments totaled $2,000. If he interchanged his investments, his \n" ); document.write( " income would increase by $340. How much did he have in each investment? \n" ); document.write( ": \n" ); document.write( "Originally: x = amt invested at 8% and y = amt invested at 6% \n" ); document.write( ": \n" ); document.write( ".08x + .06y = 2000; original income equation \n" ); document.write( ".06x + .08y = 2340; switched income equation \n" ); document.write( ": \n" ); document.write( "Multiply the 1st equation by 8, and the 2nd equation by 6; results \n" ); document.write( ".64x +.48y = 16000 \n" ); document.write( ".36x + 48y = 14040 \n" ); document.write( "----------------------subtraction eliminates y, find x \n" ); document.write( ".28x + 0y = 1960 \n" ); document.write( ": \n" ); document.write( "x = \n" ); document.write( "x = $7,000 originally invested at 8% \n" ); document.write( ": \n" ); document.write( "Find y: \n" ); document.write( ".08(7000) + .06y = 2000 \n" ); document.write( "560 + .06y = 2000 \n" ); document.write( ".06y = 2000 - 560 \n" ); document.write( ".06y = 1440 \n" ); document.write( "y = \n" ); document.write( "y = $24,000 \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check solution by switching the investments \n" ); document.write( ".08(24000) + .06(7000) = \n" ); document.write( "1920 + 420 = 2340; confirms our solutions \n" ); document.write( "; \n" ); document.write( ": \n" ); document.write( "Do you have any questions about either of these? did you understand what we did?\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |