document.write( "Question 952187: My piggy bank contains 29 coins, each of which is either a penny, nickel, dime, or quarter. The total value of all the coins is $2.86, and the number of quarters is equal to the sum of the nickels and dimes, and is less than the number of pennies. How many nickels are there? \n" ); document.write( "
Algebra.Com's Answer #581568 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! p = no.of pennies \n" ); document.write( "n = no. of nickles \n" ); document.write( "d = no. of dimes \n" ); document.write( "q = no. of quarters \n" ); document.write( ": \n" ); document.write( "write an equation for each statement \n" ); document.write( ": \n" ); document.write( " My piggy bank contains 29 coins, each of which is either a penny, nickel, dime, or quarter. \n" ); document.write( "p + n + d + q = 29 \n" ); document.write( ": \n" ); document.write( "The total value of all the coins is $2.86, \n" ); document.write( ".01p + .05n + .10d + .25q = 2.86 \n" ); document.write( ": \n" ); document.write( " and the number of quarters is equal to the sum of the nickels and dimes, \n" ); document.write( "q = n + d \n" ); document.write( "d = q - n \n" ); document.write( "n = q - d \n" ); document.write( ": \n" ); document.write( "and is less than the number of pennies. \n" ); document.write( "q < p \n" ); document.write( ": \n" ); document.write( "In the 1st equation replace n + d with q and you have \n" ); document.write( "p + 2q = 29 \n" ); document.write( "p = -2q + 29 \n" ); document.write( "From the above equation and the total$ equation we know the number of pennies has to be 21 or 11 pennies which would make it 4 or 9 quarters \n" ); document.write( ".01p + .05n + .10d + .25q = 2.86 \n" ); document.write( "lets say 9 quarters and 11 pennies \n" ); document.write( ".11 + .05n + .10d + .25(9) = 2.86 \n" ); document.write( ".11 + .05n + .10d + 2.25 = 2.86 \n" ); document.write( ".05n + .10d + 2.36 = 2.86 \n" ); document.write( ".05n + .10d = 2.86 - 2.36 \n" ); document.write( ".05n + .10d = .50 \n" ); document.write( "simplify, divide by .05 \n" ); document.write( "n + 2d = 10 \n" ); document.write( "we know the d = q - n, d = 4 - n \n" ); document.write( "n + 2(9-n) = 10 \n" ); document.write( "n + 18 - 2n = 10 \n" ); document.write( "-n = 10 - 18 \n" ); document.write( "-n = -8 \n" ); document.write( "n = 8 nickels \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check this find the dimes \n" ); document.write( "8 + 2d = 10 \n" ); document.write( "2d = 2 \n" ); document.write( "d = 1 dime \n" ); document.write( ": \n" ); document.write( "11 + 8 + 1 + 9 = 29 \n" ); document.write( "and \n" ); document.write( ".01(11) + .05(8) + .10(1) + .25(9) = 2.86 \n" ); document.write( ".11 + .40 + .10 + 2.25 = 2.86\r \n" ); document.write( "\n" ); document.write( "--------------------Response to Comment----------------------- \n" ); document.write( "Tried sending this to the given email address, came back as \"Milbox not available\" \n" ); document.write( ": \n" ); document.write( "Yes, well to start with, we have 4 unknowns and only 3 meaningful equations, which means we will have to apply some logical assumptions \n" ); document.write( "Assuming you followed me Ok up to the equation: \n" ); document.write( "p = –2q + 29 \n" ); document.write( "Since we have a total of 2.86, and the total of the rest of the coins have to be a multiple of 5, the number of pennies have to end in a 1 or a 6 \n" ); document.write( "and looking at the above equation, subtract 2q from 29 will give you an odd number of pennies less than 29 of course, leaves us with a choice of 11 or 21 pennies \n" ); document.write( "This narrows it down to a manageable, try it and see” situation \n" ); document.write( "We can find the number of quarters with either p=11 or p=21 \n" ); document.write( "-2q + 29 = 11 \n" ); document.write( "-2q = 11 – 29 \n" ); document.write( "-2q = –18 \n" ); document.write( "q = –18/-2 \n" ); document.write( "q = 9 quarters \n" ); document.write( " \n" ); document.write( "The other alternative, when p = 21 \n" ); document.write( "-2q + 29 = 21 \n" ); document.write( "-2q = 21 – 29 \n" ); document.write( "q = –8/-2 \n" ); document.write( "q = 4 quarters \n" ); document.write( " \n" ); document.write( "Hence the statement, \n" ); document.write( "”From the above equation and the total$ equation we know the number of pennies has to be 21 or 11 pennies which would make it 4 or 9 quarters” \n" ); document.write( ": \n" ); document.write( "Hopefully it made made sense to you after that. If not, email me your concerns about this, email me at ankor@att.net \n" ); document.write( " \r \n" ); document.write( "\n" ); document.write( " \r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |