5 Coins = 55 CentsDate: 01/28/97 at 22:04:44 From: Sara Subject: Five coins = 55 cents I have five coins in my pocket. together they are worth 55 cents. What coins do I have? Date: 01/29/97 at 12:30:54 From: Doctor Wilkinson Subject: Re: Five coins = 55 cents Let's think about it. First of all, you must have at least one quarter, because 5 dimes would only make 50 cents. You can't have two quarters, because that would make 50 cents. If you also had a nickel, then that would be 55 cents in just 3 coins, but if you just had pennies, 3 of them would only make 53 cents. So you must have just one quarter. That leaves four coins to make 30 cents from. Now you need at last one dime, because four nickels would only make 20 cents. In fact you need two dimes, because if you just had one dime, you would have to make 20 cents out of just three coins, and three nickels would only give you 15 cents. So now you have a quarter and two dimes, which is 45 cents. You need to make the remaining 10 cents out of two coins, and two nickels is the only possibility. So you have one quarter, two dimes, and two nickels. -Doctor Wilkinson, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/