document.write( "Question 105059: A change machine contains nickels, dimes, and quarters. There are 75 coins in the machine, and the value of the coins is $7.25. There are 5 times as many nickels as dimes. Find the number of coins of each type in the machine. \n" ); document.write( "
Algebra.Com's Answer #76513 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! : \n" ); document.write( "A change machine contains nickels, dimes, and quarters. \n" ); document.write( ": \n" ); document.write( "Just write an equation for each statement: \n" ); document.write( ": \n" ); document.write( "\"There are 75 coins in the machine,\" \n" ); document.write( "n + d + q = 75 \n" ); document.write( ": \n" ); document.write( "\"the value of the coins is $7.25.\" \n" ); document.write( ".05n + .10n + .25q = 7.25 \n" ); document.write( ": \n" ); document.write( "\" There are 5 times as many nickels as dimes.\" \n" ); document.write( "n = 5d \n" ); document.write( ": \n" ); document.write( "Find the number of coins of each type in the machine. \n" ); document.write( ": \n" ); document.write( "Substitute 5d for n in the 1st equation: \n" ); document.write( "5d + d + q = 75 \n" ); document.write( "6d + q = 75 \n" ); document.write( "q = (75-6d); use this for substitution later \n" ); document.write( ": \n" ); document.write( "Substitute 5d for n in the 2nd equation: \n" ); document.write( ".05(5d) + .10d + .25q = 7.25 \n" ); document.write( ".25d + .10d + .25q = 7.25 \n" ); document.write( ".35d + .25q = 7.25 \n" ); document.write( ": \n" ); document.write( "In the above equation substitute (75-6d) for q: \n" ); document.write( ".35d + .25(75-6d) = 7.25 \n" ); document.write( ".35d + 18.75 - 1.5d = 7.25 \n" ); document.write( ".35d - 1.5d = 7.25 - 18.75 \n" ); document.write( "-1.15d = -11.5 \n" ); document.write( "d = -11.5/-1.15 \n" ); document.write( "d = +10 dimes \n" ); document.write( ": \n" ); document.write( "Find the nickels from n = 5d \n" ); document.write( "n = 5(10) \n" ); document.write( "n = 50 nickels \n" ); document.write( ": \n" ); document.write( "Find q using the 1st equation: \n" ); document.write( "50 + 10 + q = 75 \n" ); document.write( "60 + q = 75 \n" ); document.write( "q = 75 - 60 \n" ); document.write( "q = 15 quarters \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check our solutions on the 2nd equation:. \n" ); document.write( ".05(50) + .10(10) + .25(15) = \n" ); document.write( "2.50 + 1.00 + 3.75 = 7.25; confirms our solutions \n" ); document.write( ": \n" ); document.write( "Did this makes sense to you? A lot of steps but each one is logical and simple. \n" ); document.write( "Any questions? \n" ); document.write( " |