document.write( "Question 1145667: Lucinda has a pocketful of dimes and quarters with a value of $6.20. The number of dimes is 18 more than 3 times the number of quarters. How many dimes and how many quarters does Lucinda have? \n" ); document.write( "
Algebra.Com's Answer #766894 by greenestamps(13203)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Using formal algebra.... \n" ); document.write( "d = # of dimes \n" ); document.write( "q = # of quarters \n" ); document.write( "(1) 10d+25q = 620 [the value of the dimes (10 cents each) and quarters (25 cents each) is $6.20 = 620 cents] \n" ); document.write( "(2) d = 3q+18 [the number of dimes is 18 more than 3 times the number of quarters] \n" ); document.write( "Solve the pair of equations. Probably the easiest method is to substitute (2) into (1) and solve for q; then use that value of q in either equation to solve for d. \n" ); document.write( "I leave it to you to get the practice finishing solving the problem using formal algebra. \n" ); document.write( "Using logical reasoning and simple mental arithmetic.... \n" ); document.write( "(1) Count the 18 \"extra\" dimes. Their value is 180 cents; that leaves 440 cents for the remaining coins. \n" ); document.write( "(2) The remaining coins are 3 dimes for each quarter. Imagine the remaining coins in groups each consisting of 1 quarter and 3 dimes. The value of 1 quarter and 3 dimes is 55 cents. \n" ); document.write( "(3) The number of groups at 55 cents each required to make the remaining 440 cents is 440/55 = 8. In those 8 groups there are 8 quarters and 8*3=24 dimes. \n" ); document.write( "(4) So all together there are 8 quarters and 24+18=42 dimes. \n" ); document.write( " \n" ); document.write( "(3) The number of groups of \n" ); document.write( " |