How Many Pencils?Date: 9/11/96 at 20:41:54 From: Anonymous Subject: How Many Pencils? Al is an artist who uses color pencils to sketch. How many pencils does Al have if all of them are blue except two, all of them are yellow except two, and all of them are red except two? Date: 9/11/96 at 21:56:50 From: Doctor Patrick Subject: Re: How Many Pencils? Hi! First, let me ask you a question - how many different colors does Al have? You should see that he has three colors. This means that if all of them are blue except for two, then the two that are left must be the red and the yellow. This means that there is one red and one yellow, but we don't know how many blues there are. If we look at the next statement, which says that all of them are red except for two, and there are two colors left, we again know that the two left must be for the two colors which are also left - one each. This gives us one blue, and, again, one yellow. Now we know that there is one blue, one yellow and one red. With no other colors, this adds up to three colored pencils. -Doctor Patrick, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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