Making ChangeDate: 04/15/99 at 00:25:01 From: Jeffrey Mo Subject: Perimeter/Area/Volume, word problem 1. John has a pocket full of change, yet he can't make change for a dollar, a half-dollar, a quarter, a dime, or a nickel. What is the greatest amount of money John can have in his pocket? Date: 04/15/99 at 11:19:54 From: Doctor Rob Subject: Re: Perimeter/Area/Volume, word problem Thanks for writing to Ask Dr. Math! Start by thinking about changing using only one kind of coin. If he had 5 or more pennies, he could change a nickel, so he has at most 4. If he had 2 or more nickels, he could change a dime, so he has at most 1. If he had 5 or more dimes, he could change a half-dollar, so he has at most 4. If he had 2 or more quarters, he could change a half-dollar, so he has at most 1. If he had 2 or more half-dollars, he could change a dollar, so he has at most 1. Now you have to deal with the possibilities of changing using two or more kinds of coins. Four or fewer pennies will not help changing anything, so you might as well give him the four pennies. One nickel and two dimes will change a quarter, so if he has 1 nickel, he has at most 1 dime. If he has no nickel, he has at most 4 dimes. Now put all this together. - Doctor Rob, The Math Forum http://mathforum.org/dr.math/ |
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